CINXE.COM

<!doctype html><html lang="en-US" prefix="og: https://ogp.me/ns#"><head><meta charSet="utf-8"/><meta name="viewport" content="width=device-width,initial-scale=1"/><link rel="icon" href="https://developer.mozilla.org/favicon-48x48.bc390275e955dacb2e65.png"/><link rel="apple-touch-icon" href="https://developer.mozilla.org/apple-touch-icon.528534bba673c38049c2.png"/><meta name="theme-color" content="#ffffff"/><link rel="manifest" href="https://developer.mozilla.org/manifest.f42880861b394dd4dc9b.json"/><link rel="search" type="application/opensearchdescription+xml" href="/opensearch.xml" title="MDN Web Docs"/><title>JavaScript object basics - Learn web development | MDN</title><link rel="alternate" title="JavaScript-Objektgrundlagen" href="https://developer.mozilla.org/de/docs/Learn_web_development/Core/Scripting/Object_basics" hrefLang="de"/><link rel="alternate" title="Conceptos básicos de los objetos JavaScript" href="https://developer.mozilla.org/es/docs/Learn_web_development/Core/Scripting/Object_basics" hrefLang="es"/><link rel="alternate" title="Les bases de JavaScript, orienté objet" href="https://developer.mozilla.org/fr/docs/Learn_web_development/Core/Scripting/Object_basics" hrefLang="fr"/><link rel="alternate" title="JavaScript オブジェクトの基本" href="https://developer.mozilla.org/ja/docs/Learn_web_development/Core/Scripting/Object_basics" hrefLang="ja"/><link rel="alternate" title="JavaScript 객체 기본" href="https://developer.mozilla.org/ko/docs/Learn_web_development/Core/Scripting/Object_basics" hrefLang="ko"/><link rel="alternate" title="O básico sobre objetos JavaScript" href="https://developer.mozilla.org/pt-BR/docs/Learn_web_development/Core/Scripting/Object_basics" hrefLang="pt"/><link rel="alternate" title="Основы объектов в JavaScript" href="https://developer.mozilla.org/ru/docs/Learn_web_development/Core/Scripting/Object_basics" hrefLang="ru"/><link rel="alternate" title="JavaScript 对象基础" href="https://developer.mozilla.org/zh-CN/docs/Learn_web_development/Core/Scripting/Object_basics" hrefLang="zh"/><link rel="alternate" title="JavaScript 物件基礎概念" href="https://developer.mozilla.org/zh-TW/docs/Learn_web_development/Core/Scripting/Object_basics" hrefLang="zh-Hant"/><link rel="alternate" title="JavaScript object basics" href="https://developer.mozilla.org/en-US/docs/Learn_web_development/Core/Scripting/Object_basics" hrefLang="en"/><link rel="preload" as="font" type="font/woff2" href="/static/media/Inter.var.c2fe3cb2b7c746f7966a.woff2" crossorigin=""/><link rel="alternate" type="application/rss+xml" title="MDN Blog RSS Feed" href="https://developer.mozilla.org/en-US/blog/rss.xml" hrefLang="en"/><meta name="description" content="In this article, we'll look at fundamental JavaScript object syntax, and revisit some JavaScript features that we've already seen earlier in the course, reiterating the fact that many of the features you've already dealt with are objects."/><meta property="og:url" content="https://developer.mozilla.org/en-US/docs/Learn_web_development/Core/Scripting/Object_basics"/><meta property="og:title" content="JavaScript object basics - Learn web development | MDN"/><meta property="og:type" content="website"/><meta property="og:locale" content="en_US"/><meta property="og:description" content="In this article, we'll look at fundamental JavaScript object syntax, and revisit some JavaScript features that we've already seen earlier in the course, reiterating the fact that many of the features you've already dealt with are objects."/><meta property="og:image" content="https://developer.mozilla.org/mdn-social-share.d893525a4fb5fb1f67a2.png"/><meta property="og:image:type" content="image/png"/><meta property="og:image:height" content="1080"/><meta property="og:image:width" content="1920"/><meta property="og:image:alt" content="The MDN Web Docs logo, featuring a blue accent color, displayed on a solid black background."/><meta property="og:site_name" content="MDN Web Docs"/><meta name="twitter:card" content="summary_large_image"/><meta name="twitter:creator" content="MozDevNet"/><link rel="canonical" href="https://developer.mozilla.org/en-US/docs/Learn_web_development/Core/Scripting/Object_basics"/><style media="print">.article-actions-container,.document-toc-container,.language-menu,.main-menu-toggle,.on-github,.page-footer,.place,.sidebar,.top-banner,.top-navigation-main,ul.prev-next{display:none!important}.main-page-content,.main-page-content pre{padding:2px}.main-page-content pre{border-left-width:2px}</style><script src="/static/js/gtag.js" defer=""></script><script defer="" src="/static/js/main.f565372a.js"></script><link href="/static/css/main.3d9e7a02.css" rel="stylesheet"/></head><body><script>if(document.body.addEventListener("load",(t=>{t.target.classList.contains("interactive")&&t.target.setAttribute("data-readystate","complete")}),{capture:!0}),window&&document.documentElement){const t={light:"#ffffff",dark:"#1b1b1b"};try{const e=window.localStorage.getItem("theme");e&&(document.documentElement.className=e,document.documentElement.style.backgroundColor=t[e]);const o=window.localStorage.getItem("nop");o&&(document.documentElement.dataset.nop=o)}catch(t){console.warn("Unable to read theme from localStorage",t)}}</script><div id="root"><ul id="nav-access" class="a11y-nav"><li><a id="skip-main" href="#content">Skip to main content</a></li><li><a id="skip-search" href="#top-nav-search-input">Skip to search</a></li><li><a id="skip-select-language" href="#languages-switcher-button">Skip to select language</a></li></ul><div class="page-wrapper category-javascript document-page"><div class="top-banner loading"><section class="place top container"></section></div><div class="sticky-header-container"><header class="top-navigation "><div class="container "><div class="top-navigation-wrap"><a href="/en-US/" class="logo" aria-label="MDN homepage"><svg id="mdn-docs-logo" xmlns="http://www.w3.org/2000/svg" x="0" y="0" viewBox="0 0 694.9 104.4" style="enable-background:new 0 0 694.9 104.4" xml:space="preserve" role="img"><title>MDN Web Docs</title><path d="M40.3 0 11.7 92.1H0L28.5 0h11.8zm10.4 0v92.1H40.3V0h10.4zM91 0 62.5 92.1H50.8L79.3 0H91zm10.4 0v92.1H91V0h10.4z" class="logo-m"></path><path d="M627.9 95.6h67v8.8h-67v-8.8z" class="logo-_"></path><path d="M367 42h-4l-10.7 30.8h-5.5l-10.8-26h-.4l-10.5 26h-5.2L308.7 42h-3.8v-5.6H323V42h-6.5l6.8 20.4h.4l10.3-26h4.7l11.2 26h.5l5.7-20.3h-6.2v-5.6H367V42zm34.9 20c-.4 3.2-2 5.9-4.7 8.2-2.8 2.3-6.5 3.4-11.3 3.4-5.4 0-9.7-1.6-13.1-4.7-3.3-3.2-5-7.7-5-13.7 0-5.7 1.6-10.3 4.7-14s7.4-5.5 12.9-5.5c5.1 0 9.1 1.6 11.9 4.7s4.3 6.9 4.3 11.3c0 1.5-.2 3-.5 4.7h-25.6c.3 7.7 4 11.6 10.9 11.6 2.9 0 5.1-.7 6.5-2 1.5-1.4 2.5-3 3-4.9l6 .9zM394 51.3c.2-2.4-.4-4.7-1.8-6.9s-3.8-3.3-7-3.3c-3.1 0-5.3 1-6.9 3-1.5 2-2.5 4.4-2.8 7.2H394zm51 2.4c0 5-1.3 9.5-4 13.7s-6.9 6.2-12.7 6.2c-6 0-10.3-2.2-12.7-6.7-.1.4-.2 1.4-.4 2.9s-.3 2.5-.4 2.9h-7.3c.3-1.7.6-3.5.8-5.3.3-1.8.4-3.7.4-5.5V22.3h-6v-5.6H416v27c1.1-2.2 2.7-4.1 4.7-5.7 2-1.6 4.8-2.4 8.4-2.4 4.6 0 8.4 1.6 11.4 4.7 3 3.2 4.5 7.6 4.5 13.4zm-7.7.6c0-4.2-1-7.4-3-9.5-2-2.2-4.4-3.3-7.4-3.3-3.4 0-6 1.2-8 3.7-1.9 2.4-2.9 5-3 7.7V57c0 3 1 5.6 3 7.7s4.5 3.1 7.6 3.1c3.6 0 6.3-1.3 8.1-3.9 1.8-2.7 2.7-5.9 2.7-9.6zm69.2 18.5h-13.2v-7.2c-1.2 2.2-2.8 4.1-4.9 5.6-2.1 1.6-4.8 2.4-8.3 2.4-4.8 0-8.7-1.6-11.6-4.9-2.9-3.2-4.3-7.7-4.3-13.3 0-5 1.3-9.6 4-13.7 2.6-4.1 6.9-6.2 12.8-6.2 5.7 0 9.8 2.2 12.3 6.5V22.3h-8.6v-5.6h15.8v50.6h6v5.5zM493.2 56v-4.4c-.1-3-1.2-5.5-3.2-7.3s-4.4-2.8-7.2-2.8c-3.6 0-6.3 1.3-8.2 3.9-1.9 2.6-2.8 5.8-2.8 9.6 0 4.1 1 7.3 3 9.5s4.5 3.3 7.4 3.3c3.2 0 5.8-1.3 7.8-3.8 2.1-2.6 3.1-5.3 3.2-8zm53.1-1.4c0 5.6-1.8 10.2-5.3 13.7s-8.2 5.3-13.9 5.3-10.1-1.7-13.4-5.1c-3.3-3.4-5-7.9-5-13.5 0-5.3 1.6-9.9 4.7-13.7 3.2-3.8 7.9-5.7 14.2-5.7s11 1.9 14.1 5.7c3 3.7 4.6 8.1 4.6 13.3zm-7.7-.2c0-4-1-7.2-3-9.5s-4.8-3.5-8.2-3.5c-3.6 0-6.4 1.2-8.3 3.7s-2.9 5.6-2.9 9.5c0 3.7.9 6.8 2.8 9.4 1.9 2.6 4.6 3.9 8.3 3.9 3.6 0 6.4-1.3 8.4-3.8 1.9-2.6 2.9-5.8 2.9-9.7zm45 5.8c-.4 3.2-1.9 6.3-4.4 9.1-2.5 2.9-6.4 4.3-11.8 4.3-5.2 0-9.4-1.6-12.6-4.8-3.2-3.2-4.8-7.7-4.8-13.7 0-5.5 1.6-10.1 4.7-13.9 3.2-3.8 7.6-5.7 13.2-5.7 2.3 0 4.6.3 6.7.8 2.2.5 4.2 1.5 6.2 2.9l1.5 9.5-5.9.7-1.3-6.1c-2.1-1.2-4.5-1.8-7.2-1.8-3.5 0-6.1 1.2-7.7 3.7-1.7 2.5-2.5 5.7-2.5 9.6 0 4.1.9 7.3 2.7 9.5 1.8 2.3 4.4 3.4 7.8 3.4 5.2 0 8.2-2.9 9.2-8.8l6.2 1.3zm34.7 1.9c0 3.6-1.5 6.5-4.6 8.5s-7 3-11.7 3c-5.7 0-10.6-1.2-14.6-3.6l1.2-8.8 5.7.6-.2 4.7c1.1.5 2.3.9 3.6 1.1s2.6.3 3.9.3c2.4 0 4.5-.4 6.5-1.3 1.9-.9 2.9-2.2 2.9-4.1 0-1.8-.8-3.1-2.3-3.8s-3.5-1.3-5.8-1.7-4.6-.9-6.9-1.4c-2.3-.6-4.2-1.6-5.7-2.9-1.6-1.4-2.3-3.5-2.3-6.3 0-4.1 1.5-6.9 4.6-8.5s6.4-2.4 9.9-2.4c2.6 0 5 .3 7.2.9 2.2.6 4.3 1.4 6.1 2.4l.8 8.8-5.8.7-.8-5.7c-2.3-1-4.7-1.6-7.2-1.6-2.1 0-3.7.4-5.1 1.1-1.3.8-2 2-2 3.8 0 1.7.8 2.9 2.3 3.6 1.5.7 3.4 1.2 5.7 1.6 2.2.4 4.5.8 6.7 1.4 2.2.6 4.1 1.6 5.7 3 1.4 1.6 2.2 3.7 2.2 6.6zM197.6 73.2h-17.1v-5.5h3.8V51.9c0-3.7-.7-6.3-2.1-7.9-1.4-1.6-3.3-2.3-5.7-2.3-3.2 0-5.6 1.1-7.2 3.4s-2.4 4.6-2.5 6.9v15.6h6v5.5h-17.1v-5.5h3.8V51.9c0-3.8-.7-6.4-2.1-7.9-1.4-1.5-3.3-2.3-5.6-2.3-3.2 0-5.5 1.1-7.2 3.3-1.6 2.2-2.4 4.5-2.5 6.9v15.8h6.9v5.5h-20.2v-5.5h6V42.4h-6.1v-5.6h13.4v6.4c1.2-2.1 2.7-3.8 4.7-5.2 2-1.3 4.4-2 7.3-2s5.3.7 7.5 2.1c2.2 1.4 3.7 3.5 4.5 6.4 1.1-2.5 2.7-4.5 4.9-6.1s4.8-2.4 7.9-2.4c3.5 0 6.5 1.1 8.9 3.3s3.7 5.6 3.7 10.2v18.2h6.1v5.5zm42.5 0h-13.2V66c-1.2 2.2-2.8 4.1-4.9 5.6-2.1 1.6-4.8 2.4-8.3 2.4-4.8 0-8.7-1.6-11.6-4.9-2.9-3.2-4.3-7.7-4.3-13.3 0-5 1.3-9.6 4-13.7 2.6-4.1 6.9-6.2 12.8-6.2s9.8 2.2 12.3 6.5V22.7h-8.6v-5.6h15.8v50.6h6v5.5zm-13.3-16.8V52c-.1-3-1.2-5.5-3.2-7.3s-4.4-2.8-7.2-2.8c-3.6 0-6.3 1.3-8.2 3.9-1.9 2.6-2.8 5.8-2.8 9.6 0 4.1 1 7.3 3 9.5s4.5 3.3 7.4 3.3c3.2 0 5.8-1.3 7.8-3.8 2.1-2.6 3.1-5.3 3.2-8zm61.5 16.8H269v-5.5h6V51.9c0-3.7-.7-6.3-2.2-7.9-1.4-1.6-3.4-2.3-5.7-2.3-3.1 0-5.6 1-7.4 3s-2.8 4.4-2.9 7v15.9h6v5.5h-19.3v-5.5h6V42.4h-6.2v-5.6h13.6V43c2.6-4.6 6.8-6.9 12.7-6.9 3.6 0 6.7 1.1 9.2 3.3s3.7 5.6 3.7 10.2v18.2h6v5.4h-.2z" class="logo-text"></path></svg></a><button title="Open main menu" type="button" class="button action has-icon main-menu-toggle" aria-haspopup="menu" aria-label="Open main menu" aria-expanded="false"><span class="button-wrap"><span class="icon icon-menu "></span><span class="visually-hidden">Open main menu</span></span></button></div><div class="top-navigation-main"><nav class="main-nav" aria-label="Main menu"><ul class="main-menu nojs"><li class="top-level-entry-container "><button type="button" id="references-button" class="top-level-entry menu-toggle" aria-controls="references-menu" aria-expanded="false">References</button><a href="/en-US/docs/Web" class="top-level-entry">References</a><ul id="references-menu" class="submenu references hidden inline-submenu-lg" aria-labelledby="references-button"><li class="apis-link-container mobile-only "><a href="/en-US/docs/Web" class="submenu-item "><div class="submenu-icon"></div><div class="submenu-content-container"><div class="submenu-item-heading">Overview / Web Technology</div><p class="submenu-item-description">Web technology reference for developers</p></div></a></li><li class="html-link-container "><a href="/en-US/docs/Web/HTML" class="submenu-item "><div class="submenu-icon html"></div><div class="submenu-content-container"><div class="submenu-item-heading">HTML</div><p class="submenu-item-description">Structure of content on the web</p></div></a></li><li class="css-link-container "><a href="/en-US/docs/Web/CSS" class="submenu-item "><div class="submenu-icon css"></div><div class="submenu-content-container"><div class="submenu-item-heading">CSS</div><p class="submenu-item-description">Code used to describe document style</p></div></a></li><li class="javascript-link-container "><a href="/en-US/docs/Web/JavaScript" class="submenu-item "><div class="submenu-icon javascript"></div><div class="submenu-content-container"><div class="submenu-item-heading">JavaScript</div><p class="submenu-item-description">General-purpose scripting language</p></div></a></li><li class="http-link-container "><a href="/en-US/docs/Web/HTTP" class="submenu-item "><div class="submenu-icon http"></div><div class="submenu-content-container"><div class="submenu-item-heading">HTTP</div><p class="submenu-item-description">Protocol for transmitting web resources</p></div></a></li><li class="apis-link-container "><a href="/en-US/docs/Web/API" class="submenu-item "><div class="submenu-icon apis"></div><div class="submenu-content-container"><div class="submenu-item-heading">Web APIs</div><p class="submenu-item-description">Interfaces for building web applications</p></div></a></li><li class="apis-link-container "><a href="/en-US/docs/Mozilla/Add-ons/WebExtensions" class="submenu-item "><div class="submenu-icon"></div><div class="submenu-content-container"><div class="submenu-item-heading">Web Extensions</div><p class="submenu-item-description">Developing extensions for web browsers</p></div></a></li><li class=" "><a href="/en-US/docs/Web/Accessibility" class="submenu-item "><div class="submenu-icon"></div><div class="submenu-content-container"><div class="submenu-item-heading">Accessibility</div><p class="submenu-item-description">Build web projects usable for all</p></div></a></li><li class="apis-link-container desktop-only "><a href="/en-US/docs/Web" class="submenu-item "><div class="submenu-icon"></div><div class="submenu-content-container"><div class="submenu-item-heading">Web Technology</div><p class="submenu-item-description">Web technology reference for developers</p></div></a></li></ul></li><li class="top-level-entry-container active"><button type="button" id="learn-button" class="top-level-entry menu-toggle" aria-controls="learn-menu" aria-expanded="false">Learn</button><a href="/en-US/docs/Learn_web_development" class="top-level-entry">Learn</a><ul id="learn-menu" class="submenu learn hidden inline-submenu-lg" aria-labelledby="learn-button"><li class="apis-link-container mobile-only "><a href="/en-US/docs/Learn_web_development" class="submenu-item "><div class="submenu-icon learn"></div><div class="submenu-content-container"><div class="submenu-item-heading">Overview / MDN Learning Area</div><p class="submenu-item-description">Learn web development</p></div></a></li><li class="apis-link-container desktop-only "><a href="/en-US/docs/Learn_web_development" class="submenu-item "><div class="submenu-icon learn"></div><div class="submenu-content-container"><div class="submenu-item-heading">MDN Learning Area</div><p class="submenu-item-description">Learn web development</p></div></a></li><li class="html-link-container "><a href="/en-US/docs/Learn_web_development/Core/Structuring_content" class="submenu-item "><div class="submenu-icon html"></div><div class="submenu-content-container"><div class="submenu-item-heading">HTML</div><p class="submenu-item-description">Learn to structure web content with HTML</p></div></a></li><li class="css-link-container "><a href="/en-US/docs/Learn_web_development/Core/Styling_basics" class="submenu-item "><div class="submenu-icon css"></div><div class="submenu-content-container"><div class="submenu-item-heading">CSS</div><p class="submenu-item-description">Learn to style content using CSS</p></div></a></li><li class="javascript-link-container "><a href="/en-US/docs/Learn_web_development/Core/Scripting" class="submenu-item "><div class="submenu-icon javascript"></div><div class="submenu-content-container"><div class="submenu-item-heading">JavaScript</div><p class="submenu-item-description">Learn to run scripts in the browser</p></div></a></li><li class=" "><a href="/en-US/docs/Learn_web_development/Core/Accessibility" class="submenu-item "><div class="submenu-icon"></div><div class="submenu-content-container"><div class="submenu-item-heading">Accessibility</div><p class="submenu-item-description">Learn to make the web accessible to all</p></div></a></li></ul></li><li class="top-level-entry-container "><button type="button" id="mdn-plus-button" class="top-level-entry menu-toggle" aria-controls="mdn-plus-menu" aria-expanded="false">Plus</button><a href="/en-US/plus" class="top-level-entry">Plus</a><ul id="mdn-plus-menu" class="submenu mdn-plus hidden inline-submenu-lg" aria-labelledby="mdn-plus-button"><li class=" "><a href="/en-US/plus" class="submenu-item "><div class="submenu-icon"></div><div class="submenu-content-container"><div class="submenu-item-heading">Overview</div><p class="submenu-item-description">A customized MDN experience</p></div></a></li><li class=" "><a href="/en-US/plus/ai-help" class="submenu-item "><div class="submenu-icon"></div><div class="submenu-content-container"><div class="submenu-item-heading">AI Help</div><p class="submenu-item-description">Get real-time assistance and support</p></div></a></li><li class=" "><a href="/en-US/plus/updates" class="submenu-item "><div class="submenu-icon"></div><div class="submenu-content-container"><div class="submenu-item-heading">Updates</div><p class="submenu-item-description">All browser compatibility updates at a glance</p></div></a></li><li class=" "><a href="/en-US/plus/docs/features/overview" class="submenu-item "><div class="submenu-icon"></div><div class="submenu-content-container"><div class="submenu-item-heading">Documentation</div><p class="submenu-item-description">Learn how to use MDN Plus</p></div></a></li><li class=" "><a href="/en-US/plus/docs/faq" class="submenu-item "><div class="submenu-icon"></div><div class="submenu-content-container"><div class="submenu-item-heading">FAQ</div><p class="submenu-item-description">Frequently asked questions about MDN Plus</p></div></a></li></ul></li><li class="top-level-entry-container "><a class="top-level-entry menu-link" href="/en-US/curriculum/">Curriculum <sup class="new">New</sup></a></li><li class="top-level-entry-container "><a class="top-level-entry menu-link" href="/en-US/blog/">Blog</a></li><li class="top-level-entry-container "><button type="button" id="tools-button" class="top-level-entry menu-toggle" aria-controls="tools-menu" aria-expanded="false">Tools</button><ul id="tools-menu" class="submenu tools hidden inline-submenu-lg" aria-labelledby="tools-button"><li class=" "><a href="/en-US/play" class="submenu-item "><div class="submenu-icon"></div><div class="submenu-content-container"><div class="submenu-item-heading">Playground</div><p class="submenu-item-description">Write, test and share your code</p></div></a></li><li class=" "><a href="/en-US/observatory" class="submenu-item "><div class="submenu-icon"></div><div class="submenu-content-container"><div class="submenu-item-heading">HTTP Observatory</div><p class="submenu-item-description">Scan a website for free</p></div></a></li><li class=" "><a href="/en-US/plus/ai-help" class="submenu-item "><div class="submenu-icon"></div><div class="submenu-content-container"><div class="submenu-item-heading">AI Help</div><p class="submenu-item-description">Get real-time assistance and support</p></div></a></li></ul></li></ul></nav><div class="header-search"><form action="/en-US/search" class="search-form search-widget" id="top-nav-search-form" role="search"><label id="top-nav-search-label" for="top-nav-search-input" class="visually-hidden">Search MDN</label><input aria-activedescendant="" aria-autocomplete="list" aria-controls="top-nav-search-menu" aria-expanded="false" aria-labelledby="top-nav-search-label" autoComplete="off" id="top-nav-search-input" role="combobox" type="search" class="search-input-field" name="q" placeholder=" " required="" value=""/><button type="button" class="button action has-icon clear-search-button"><span class="button-wrap"><span class="icon icon-cancel "></span><span class="visually-hidden">Clear search input</span></span></button><button type="submit" class="button action has-icon search-button"><span class="button-wrap"><span class="icon icon-search "></span><span class="visually-hidden">Search</span></span></button><div id="top-nav-search-menu" role="listbox" aria-labelledby="top-nav-search-label"></div></form></div><div class="theme-switcher-menu"><button type="button" class="button action has-icon theme-switcher-menu small" aria-haspopup="menu"><span class="button-wrap"><span class="icon icon-theme-os-default "></span>Theme</span></button></div><ul class="auth-container"><li><a href="/users/fxa/login/authenticate/?next=%2Fen-US%2Fdocs%2FLearn_web_development%2FCore%2FScripting%2FObject_basics" class="login-link" rel="nofollow">Log in</a></li><li><a href="/users/fxa/login/authenticate/?next=%2Fen-US%2Fdocs%2FLearn_web_development%2FCore%2FScripting%2FObject_basics" target="_self" rel="nofollow" class="button primary mdn-plus-subscribe-link"><span class="button-wrap">Sign up for free</span></a></li></ul></div></div></header><div class="article-actions-container"><div class="container"><button type="button" class="button action has-icon sidebar-button" aria-label="Expand sidebar" aria-expanded="false" aria-controls="sidebar-quicklinks"><span class="button-wrap"><span class="icon icon-sidebar "></span></span></button><nav class="breadcrumbs-container" aria-label="Breadcrumb"><ol typeof="BreadcrumbList" vocab="https://schema.org/" aria-label="breadcrumbs"><li property="itemListElement" typeof="ListItem"><a href="/en-US/docs/Learn_web_development" class="breadcrumb" property="item" typeof="WebPage"><span property="name">Learn</span></a><meta property="position" content="1"/></li><li property="itemListElement" typeof="ListItem"><a href="/en-US/docs/Learn_web_development/Core" class="breadcrumb" property="item" typeof="WebPage"><span property="name">Core learning modules</span></a><meta property="position" content="2"/></li><li property="itemListElement" typeof="ListItem"><a href="/en-US/docs/Learn_web_development/Core/Scripting" class="breadcrumb" property="item" typeof="WebPage"><span property="name">Dynamic scripting with JavaScript</span></a><meta property="position" content="3"/></li><li property="itemListElement" typeof="ListItem"><a href="/en-US/docs/Learn_web_development/Core/Scripting/Object_basics" class="breadcrumb-current-page" property="item" typeof="WebPage"><span property="name">JavaScript object basics</span></a><meta property="position" content="4"/></li></ol></nav><div class="article-actions"><button type="button" class="button action has-icon article-actions-toggle" aria-label="Article actions"><span class="button-wrap"><span class="icon icon-ellipses "></span><span class="article-actions-dialog-heading">Article Actions</span></span></button><ul class="article-actions-entries"><li class="article-actions-entry"><div class="languages-switcher-menu open-on-focus-within"><button id="languages-switcher-button" type="button" class="button action small has-icon languages-switcher-menu" aria-haspopup="menu"><span class="button-wrap"><span class="icon icon-language "></span>English (US)</span></button><div class="hidden"><ul class="submenu language-menu " aria-labelledby="language-menu-button"><li class=" "><form class="submenu-item locale-redirect-setting"><div class="group"><label class="switch"><input type="checkbox" name="locale-redirect"/><span class="slider"></span><span class="label">Remember language</span></label><a href="https://github.com/orgs/mdn/discussions/739" rel="external noopener noreferrer" target="_blank" title="Enable this setting to automatically switch to this language when it's available. (Click to learn more.)"><span class="icon icon-question-mark "></span></a></div></form></li><li class=" "><a data-locale="de" href="/de/docs/Learn_web_development/Core/Scripting/Object_basics" class="button submenu-item"><span>Deutsch</span><span title="Diese Übersetzung ist Teil eines Experiments."><span class="icon icon-experimental "></span></span></a></li><li class=" "><a data-locale="es" href="/es/docs/Learn_web_development/Core/Scripting/Object_basics" class="button submenu-item"><span>Español</span></a></li><li class=" "><a data-locale="fr" href="/fr/docs/Learn_web_development/Core/Scripting/Object_basics" class="button submenu-item"><span>Français</span></a></li><li class=" "><a data-locale="ja" href="/ja/docs/Learn_web_development/Core/Scripting/Object_basics" class="button submenu-item"><span>日本語</span></a></li><li class=" "><a data-locale="ko" href="/ko/docs/Learn_web_development/Core/Scripting/Object_basics" class="button submenu-item"><span>한국어</span></a></li><li class=" "><a data-locale="pt-BR" href="/pt-BR/docs/Learn_web_development/Core/Scripting/Object_basics" class="button submenu-item"><span>Português (do Brasil)</span></a></li><li class=" "><a data-locale="ru" href="/ru/docs/Learn_web_development/Core/Scripting/Object_basics" class="button submenu-item"><span>Русский</span></a></li><li class=" "><a data-locale="zh-CN" href="/zh-CN/docs/Learn_web_development/Core/Scripting/Object_basics" class="button submenu-item"><span>中文 (简体)</span></a></li><li class=" "><a data-locale="zh-TW" href="/zh-TW/docs/Learn_web_development/Core/Scripting/Object_basics" class="button submenu-item"><span>正體中文 (繁體)</span></a></li></ul></div></div></li></ul></div></div></div></div><div class="main-wrapper"><div class="sidebar-container"><aside id="sidebar-quicklinks" class="sidebar"><button type="button" class="button action backdrop" aria-label="Collapse sidebar"><span class="button-wrap"></span></button><nav aria-label="Related Topics" class="sidebar-inner"><header class="sidebar-actions"><section class="sidebar-filter-container"><div class="sidebar-filter "><label id="sidebar-filter-label" class="sidebar-filter-label" for="sidebar-filter-input"><span class="icon icon-filter"></span><span class="visually-hidden">Filter sidebar</span></label><input id="sidebar-filter-input" autoComplete="off" class="sidebar-filter-input-field false" type="text" placeholder="Filter" value=""/><button type="button" class="button action has-icon clear-sidebar-filter-button"><span class="button-wrap"><span class="icon icon-cancel "></span><span class="visually-hidden">Clear filter input</span></span></button></div></section></header><div class="sidebar-inner-nav"><div class="in-nav-toc"><div class="document-toc-container"><section class="document-toc"><header><h2 class="document-toc-heading">In this article</h2></header><ul class="document-toc-list"><li class="document-toc-item "><a class="document-toc-link" href="#object_basics">Object basics</a></li><li class="document-toc-item "><a class="document-toc-link" href="#dot_notation">Dot notation</a></li><li class="document-toc-item "><a class="document-toc-link" href="#bracket_notation">Bracket notation</a></li><li class="document-toc-item "><a class="document-toc-link" href="#setting_object_members">Setting object members</a></li><li class="document-toc-item "><a class="document-toc-link" href="#what_is_this">What is "this"?</a></li><li class="document-toc-item "><a class="document-toc-link" href="#introducing_constructors">Introducing constructors</a></li><li class="document-toc-item "><a class="document-toc-link" href="#youve_been_using_objects_all_along">You've been using objects all along</a></li><li class="document-toc-item "><a class="document-toc-link" href="#test_your_skills!">Test your skills!</a></li><li class="document-toc-item "><a class="document-toc-link" href="#summary">Summary</a></li></ul></section></div></div><div class="sidebar-body"><ol><li class="section"><a href="/en-US/docs/Learn_web_development/Getting_started">Getting started modules</a></li><li class="toggle"><details><summary><a href="/en-US/docs/Learn_web_development/Getting_started/Environment_setup">Environment setup</a></summary><ol><li><a href="/en-US/docs/Learn_web_development/Getting_started/Environment_setup/Installing_software">Installing basic software</a></li><li><a href="/en-US/docs/Learn_web_development/Getting_started/Environment_setup/Browsing_the_web">Browsing the web</a></li><li><a href="/en-US/docs/Learn_web_development/Getting_started/Environment_setup/Code_editors">Code editors</a></li><li><a href="/en-US/docs/Learn_web_development/Getting_started/Environment_setup/Dealing_with_files">Dealing with files</a></li><li><a href="/en-US/docs/Learn_web_development/Getting_started/Environment_setup/Command_line">Command line crash course</a></li></ol></details></li><li class="toggle"><details><summary><a href="/en-US/docs/Learn_web_development/Getting_started/Your_first_website">Your first website</a></summary><ol><li><a href="/en-US/docs/Learn_web_development/Getting_started/Your_first_website/What_will_your_website_look_like">What will your website look like?</a></li><li><a href="/en-US/docs/Learn_web_development/Getting_started/Your_first_website/Creating_the_content">HTML: Creating the content</a></li><li><a href="/en-US/docs/Learn_web_development/Getting_started/Your_first_website/Styling_the_content">CSS: Styling the content</a></li><li><a href="/en-US/docs/Learn_web_development/Getting_started/Your_first_website/Adding_interactivity">JavaScript: Adding interactivity</a></li><li><a href="/en-US/docs/Learn_web_development/Getting_started/Your_first_website/Publishing_your_website">Publishing your website</a></li></ol></details></li><li class="toggle"><details><summary><a href="/en-US/docs/Learn_web_development/Getting_started/Web_standards">Web standards</a></summary><ol><li><a href="/en-US/docs/Learn_web_development/Getting_started/Web_standards/How_the_web_works">How the web works</a></li><li><a href="/en-US/docs/Learn_web_development/Getting_started/Web_standards/The_web_standards_model">The web standards model</a></li><li><a href="/en-US/docs/Learn_web_development/Getting_started/Web_standards/How_browsers_load_websites">How browsers load websites</a></li></ol></details></li><li class="toggle"><details><summary><a href="/en-US/docs/Learn_web_development/Getting_started/Soft_skills">Soft skills</a></summary><ol><li><a href="/en-US/docs/Learn_web_development/Getting_started/Soft_skills/Research_and_learning">Research and learning</a></li><li><a href="/en-US/docs/Learn_web_development/Getting_started/Soft_skills/Collaboration_and_teamwork">Collaboration and teamwork</a></li><li><a href="/en-US/docs/Learn_web_development/Getting_started/Soft_skills/Workflows_and_processes">Workflows and processes</a></li><li><a href="/en-US/docs/Learn_web_development/Getting_started/Soft_skills/Job_interviews">Succeeding in job interviews</a></li></ol></details></li><li class="section"><a href="/en-US/docs/Learn_web_development/Core">Core modules</a></li><li class="toggle"><details><summary><a href="/en-US/docs/Learn_web_development/Core/Structuring_content">Structuring content with HTML</a></summary><ol><li><a href="/en-US/docs/Learn_web_development/Core/Structuring_content/Basic_HTML_syntax">Basic HTML syntax</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Structuring_content/Webpage_metadata">What's in the head? Webpage metadata</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Structuring_content/Headings_and_paragraphs">Headings and paragraphs in HTML</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Structuring_content/Emphasis_and_importance">Emphasis and importance</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Structuring_content/Lists">Lists</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Structuring_content/Structuring_documents">Structuring documents</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Structuring_content/Advanced_text_features">Advanced text features</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Structuring_content/Creating_links">Creating links</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Structuring_content/Marking_up_a_letter">Challenge: Marking up a letter</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Structuring_content/Structuring_a_page_of_content">Challenge: Structuring a page of content</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Structuring_content/HTML_images">HTML images</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Structuring_content/HTML_video_and_audio">HTML video and audio</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Structuring_content/Mozilla_splash_page">Challenge: Mozilla splash page</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Structuring_content/HTML_table_basics">HTML table basics</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Structuring_content/Table_accessibility">HTML table accessibility</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Structuring_content/Planet_data_table">Challenge: Structuring a planet data table</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Structuring_content/HTML_forms">Forms and buttons in HTML</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Structuring_content/Debugging_HTML">Debugging HTML</a></li></ol></details></li><li class="toggle"><details><summary><a href="/en-US/docs/Learn_web_development/Core/Styling_basics">CSS styling basics</a></summary><ol><li><a href="/en-US/docs/Learn_web_development/Core/Styling_basics/What_is_CSS">What is CSS?</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Styling_basics/Getting_started">Getting started with CSS</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Styling_basics/Styling_a_bio_page">Challenge: Styling a biography page</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Styling_basics/Basic_selectors">Basic CSS selectors</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Styling_basics/Attribute_selectors">Attribute selectors</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Styling_basics/Pseudo_classes_and_elements">Pseudo-classes and pseudo-elements</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Styling_basics/Combinators">Combinators</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Styling_basics/Box_model">The box model</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Styling_basics/Handling_conflicts">Handling conflicts</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Styling_basics/Values_and_units">CSS values and units</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Styling_basics/Sizing">Sizing items in CSS</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Styling_basics/Backgrounds_and_borders">Backgrounds and borders</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Styling_basics/Overflow">Overflowing content</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Styling_basics/Images_media_forms">Images, media, and form elements</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Styling_basics/Tables">Styling tables</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Styling_basics/Debugging_CSS">Debugging CSS</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Styling_basics/Fundamental_CSS_comprehension">Challenge: Fundamental CSS comprehension</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Styling_basics/Fancy_letterheaded_paper">Challenge: Creating fancy letterheaded paper</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Styling_basics/Cool-looking_box">Challenge: A cool-looking box</a></li></ol></details></li><li class="toggle"><details><summary><a href="/en-US/docs/Learn_web_development/Core/Text_styling">CSS text styling</a></summary><ol><li><a href="/en-US/docs/Learn_web_development/Core/Text_styling/Fundamentals">Fundamental text and font styling</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Text_styling/Styling_lists">Styling lists</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Text_styling/Styling_links">Styling links</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Text_styling/Web_fonts">Web fonts</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Text_styling/Typesetting_a_homepage">Challenge: Typesetting a community school homepage</a></li></ol></details></li><li class="toggle"><details><summary><a href="/en-US/docs/Learn_web_development/Core/CSS_layout">CSS layout</a></summary><ol><li><a href="/en-US/docs/Learn_web_development/Core/CSS_layout/Introduction">Introduction to CSS layout</a></li><li><a href="/en-US/docs/Learn_web_development/Core/CSS_layout/Floats">Floats</a></li><li><a href="/en-US/docs/Learn_web_development/Core/CSS_layout/Positioning">Positioning</a></li><li><a href="/en-US/docs/Learn_web_development/Core/CSS_layout/Flexbox">Flexbox</a></li><li><a href="/en-US/docs/Learn_web_development/Core/CSS_layout/Grids">CSS grid layout</a></li><li><a href="/en-US/docs/Learn_web_development/Core/CSS_layout/Responsive_Design">Responsive design</a></li><li><a href="/en-US/docs/Learn_web_development/Core/CSS_layout/Media_queries">Media query fundamentals</a></li><li><a href="/en-US/docs/Learn_web_development/Core/CSS_layout/Fundamental_Layout_Comprehension">Challenge: Fundamental layout comprehension</a></li></ol></details></li><li class="toggle"><details open=""><summary><a href="/en-US/docs/Learn_web_development/Core/Scripting">Dynamic scripting with JavaScript</a></summary><ol><li><a href="/en-US/docs/Learn_web_development/Core/Scripting/What_is_JavaScript">What is JavaScript?</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Scripting/A_first_splash">A first splash into JavaScript</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Scripting/What_went_wrong">What went wrong? Troubleshooting JavaScript</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Scripting/Variables">Storing the information you need — Variables</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Scripting/Math">Basic math in JavaScript — numbers and operators</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Scripting/Strings">Handling text — strings in JavaScript</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Scripting/Useful_string_methods">Useful string methods</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Scripting/Arrays">Arrays</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Scripting/Silly_story_generator">Challenge: Silly story generator</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Scripting/Conditionals">Making decisions in your code — conditionals</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Scripting/Loops">Looping code</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Scripting/Functions">Functions — reusable blocks of code</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Scripting/Build_your_own_function">Build your own function</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Scripting/Return_values">Function return values</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Scripting/Events">Introduction to events</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Scripting/Event_bubbling">Event bubbling</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Scripting/Image_gallery">Challenge: Image gallery</a></li><li><em><a href="/en-US/docs/Learn_web_development/Core/Scripting/Object_basics" aria-current="page">JavaScript object basics</a></em></li><li><a href="/en-US/docs/Learn_web_development/Core/Scripting/DOM_scripting">DOM scripting introduction</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Scripting/Network_requests">Making network requests with JavaScript</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Scripting/JSON">Working with JSON</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Scripting/Debugging_JavaScript">Debugging JavaScript and handling errors</a></li></ol></details></li><li class="toggle"><details><summary><a href="/en-US/docs/Learn_web_development/Core/Frameworks_libraries">JavaScript frameworks and libraries</a></summary><ol><li><a href="/en-US/docs/Learn_web_development/Core/Frameworks_libraries/Introduction">Introduction to client-side frameworks</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Frameworks_libraries/Main_features">Framework main features</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Frameworks_libraries/React_getting_started">Getting started with React</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Frameworks_libraries/React_todo_list_beginning">Beginning our React todo list</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Frameworks_libraries/React_components">Componentizing our React app</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Frameworks_libraries/React_interactivity_events_state">React interactivity: Events and state</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Frameworks_libraries/React_interactivity_filtering_conditional_rendering">React interactivity: Editing, filtering, conditional rendering</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Frameworks_libraries/React_accessibility">Accessibility in React</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Frameworks_libraries/React_resources">React resources</a></li></ol></details></li><li class="toggle"><details><summary><a href="/en-US/docs/Learn_web_development/Core/Accessibility">Accessibility</a></summary><ol><li><a href="/en-US/docs/Learn_web_development/Core/Accessibility/What_is_accessibility">What is accessibility?</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Accessibility/Tooling">Accessibility tooling and assistive technology</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Accessibility/HTML">HTML: A good basis for accessibility</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Accessibility/CSS_and_JavaScript">CSS and JavaScript accessibility best practices</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Accessibility/WAI-ARIA_basics">WAI-ARIA basics</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Accessibility/Multimedia">Accessible multimedia</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Accessibility/Mobile">Mobile accessibility</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Accessibility/Accessibility_troubleshooting">Challenge: Accessibility troubleshooting</a></li></ol></details></li><li><a href="/en-US/docs/Learn_web_development/Core/Design_for_developers">Design for developers</a></li><li><a href="/en-US/docs/Learn_web_development/Core/Version_control">Version control</a></li><li class="section"><a href="/en-US/docs/Learn_web_development/Extensions">Extension modules</a></li><li class="toggle"><details><summary><a href="/en-US/docs/Learn_web_development/Extensions/Advanced_JavaScript_objects">Advanced JavaScript objects</a></summary><ol><li><a href="/en-US/docs/Learn_web_development/Extensions/Advanced_JavaScript_objects/Object_prototypes">Object prototypes</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Advanced_JavaScript_objects/Object-oriented_programming">Object-oriented programming</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Advanced_JavaScript_objects/Classes_in_JavaScript">Classes in JavaScript</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Advanced_JavaScript_objects/Object_building_practice">Object building practice</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Advanced_JavaScript_objects/Adding_bouncing_balls_features">Challenge: Adding features to our bouncing balls demo</a></li></ol></details></li><li class="toggle"><details><summary><a href="/en-US/docs/Learn_web_development/Extensions/Client-side_APIs">Client-side web APIs</a></summary><ol><li><a href="/en-US/docs/Learn_web_development/Extensions/Client-side_APIs/Introduction">Introduction to web APIs</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Client-side_APIs/Video_and_audio_APIs">Video and Audio APIs</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Client-side_APIs/Drawing_graphics">Drawing graphics</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Client-side_APIs/Client-side_storage">Client-side storage</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Client-side_APIs/Third_party_APIs">Third-party APIs</a></li></ol></details></li><li class="toggle"><details><summary><a href="/en-US/docs/Learn_web_development/Extensions/Async_JS">Asynchronous JavaScript</a></summary><ol><li><a href="/en-US/docs/Learn_web_development/Extensions/Async_JS/Introducing">Introducing asynchronous JavaScript</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Async_JS/Promises">How to use promises</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Async_JS/Implementing_a_promise-based_API">How to implement a promise-based API</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Async_JS/Introducing_workers">Introducing workers</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Async_JS/Sequencing_animations">Challenge: Sequencing animations</a></li></ol></details></li><li class="toggle"><details><summary><a href="/en-US/docs/Learn_web_development/Extensions/Forms">Web forms</a></summary><ol><li><a href="/en-US/docs/Learn_web_development/Extensions/Forms/Your_first_form">Your first form</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Forms/How_to_structure_a_web_form">How to structure a web form</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Forms/Basic_native_form_controls">Basic native form controls</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Forms/HTML5_input_types">The HTML5 input types</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Forms/Other_form_controls">Other form controls</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Forms/Styling_web_forms">Styling web forms</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Forms/Advanced_form_styling">Advanced form styling</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Forms/UI_pseudo-classes">UI pseudo-classes</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Forms/Form_validation">Client-side form validation</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Forms/Sending_and_retrieving_form_data">Sending form data</a></li></ol></details></li><li class="toggle"><details><summary><a href="/en-US/docs/Learn_web_development/Extensions/Client-side_tools">Understanding client-side tools</a></summary><ol><li><a href="/en-US/docs/Learn_web_development/Extensions/Client-side_tools/Overview">Client-side tooling overview</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Client-side_tools/Package_management">Package management basics</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Client-side_tools/Introducing_complete_toolchain">Introducing a complete toolchain</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Client-side_tools/Deployment">Deploying our app</a></li></ol></details></li><li class="toggle"><details><summary><a href="/en-US/docs/Learn_web_development/Extensions/Server-side">Server-side websites</a></summary><ol><li class="toggle"><details><summary><a href="/en-US/docs/Learn_web_development/Extensions/Server-side/First_steps">Server-side first steps</a></summary><ol><li><a href="/en-US/docs/Learn_web_development/Extensions/Server-side/First_steps/Introduction">Introduction to the server side</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Server-side/First_steps/Client-Server_overview">Client-Server Overview</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Server-side/First_steps/Web_frameworks">Server-side web frameworks</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Server-side/First_steps/Website_security">Website security</a></li></ol></details></li><li class="toggle"><details><summary><a href="/en-US/docs/Learn_web_development/Extensions/Server-side/Django">Django web framework (Python)</a></summary><ol><li><a href="/en-US/docs/Learn_web_development/Extensions/Server-side/Django/Introduction">Django introduction</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Server-side/Django/development_environment">Setting up a Django development environment</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Server-side/Django/Tutorial_local_library_website">Django Tutorial: The Local Library website</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Server-side/Django/skeleton_website">Django Tutorial Part 2: Creating a skeleton website</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Server-side/Django/Models">Django Tutorial Part 3: Using models</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Server-side/Django/Admin_site">Django Tutorial Part 4: Django admin site</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Server-side/Django/Home_page">Django Tutorial Part 5: Creating our home page</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Server-side/Django/Generic_views">Django Tutorial Part 6: Generic list and detail views</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Server-side/Django/Sessions">Django Tutorial Part 7: Sessions framework</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Server-side/Django/Authentication">Django Tutorial Part 8: User authentication and permissions</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Server-side/Django/Forms">Django Tutorial Part 9: Working with forms</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Server-side/Django/Testing">Django Tutorial Part 10: Testing a Django web application</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Server-side/Django/Deployment">Django Tutorial Part 11: Deploying Django to production</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Server-side/Django/web_application_security">Django web application security</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Server-side/Django/django_assessment_blog">Assessment: DIY Django mini blog</a></li></ol></details></li><li class="toggle"><details><summary><a href="/en-US/docs/Learn_web_development/Extensions/Server-side/Express_Nodejs">Express web framework (Node.js)</a></summary><ol><li><a href="/en-US/docs/Learn_web_development/Extensions/Server-side/Express_Nodejs/Introduction">Express/Node introduction</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Server-side/Express_Nodejs/development_environment">Setting up a Node development environment</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Server-side/Express_Nodejs/Tutorial_local_library_website">Express Tutorial: The Local Library website</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Server-side/Express_Nodejs/skeleton_website">Express Tutorial Part 2: Creating a skeleton website</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Server-side/Express_Nodejs/mongoose">Express Tutorial Part 3: Using a Database (with Mongoose)</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Server-side/Express_Nodejs/routes">Express Tutorial Part 4: Routes and controllers</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Server-side/Express_Nodejs/Displaying_data">Express Tutorial Part 5: Displaying library data</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Server-side/Express_Nodejs/forms">Express Tutorial Part 6: Working with forms</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Server-side/Express_Nodejs/deployment">Express Tutorial Part 7: Deploying to production</a></li></ol></details></li></ol></details></li><li class="toggle"><details><summary><a href="/en-US/docs/Learn_web_development/Extensions/Performance">Web performance</a></summary><ol><li><a href="/en-US/docs/Learn_web_development/Extensions/Performance/why_web_performance">The "why" of web performance</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Performance/What_is_web_performance">What is web performance?</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Performance/Perceived_performance">Perceived performance</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Performance/Measuring_performance">Measuring performance</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Performance/Multimedia">Multimedia: Images</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Performance/video">Multimedia: video</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Performance/JavaScript">JavaScript performance optimization</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Performance/HTML">HTML performance optimization</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Performance/CSS">CSS performance optimization</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Performance/business_case_for_performance">The business case for web performance</a></li></ol></details></li><li class="toggle"><details><summary><a href="/en-US/docs/Learn_web_development/Extensions/Testing">Testing</a></summary><ol><li><a href="/en-US/docs/Learn_web_development/Extensions/Testing/Introduction">Introduction to cross-browser testing</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Testing/Testing_strategies">Strategies for carrying out testing</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Testing/HTML_and_CSS">Handling common HTML and CSS problems</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Testing/Feature_detection">Implementing feature detection</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Testing/Automated_testing">Introduction to automated testing</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Testing/Your_own_automation_environment">Setting up your own test automation environment</a></li></ol></details></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Transform_animate">Transform and animate CSS</a></li><li><a href="/en-US/docs/Learn_web_development/Extensions/Security_privacy">Security and privacy</a></li><li class="section">Further resources</li><li class="toggle"><details><summary><a href="/en-US/docs/Learn_web_development/Howto">How to solve common problems</a></summary><ol><li><a href="/en-US/docs/Learn_web_development/Howto/Solve_HTML_problems">Solve common HTML problems</a></li><li><a href="/en-US/docs/Learn_web_development/Howto/Solve_CSS_problems">Solve common CSS problems</a></li><li><a href="/en-US/docs/Learn_web_development/Howto/Solve_JavaScript_problems">Solve common JavaScript problems</a></li><li><a href="/en-US/docs/Learn_web_development/Howto/Web_mechanics">Web mechanics</a></li><li><a href="/en-US/docs/Learn_web_development/Howto/Tools_and_setup">Tools and setup</a></li><li><a href="/en-US/docs/Learn_web_development/Howto/Design_and_accessibility">Design and accessibility</a></li></ol></details></li><li><a href="/en-US/docs/Learn_web_development/About">About</a></li><li><a href="/en-US/docs/Learn_web_development/Educators">Resources for educators</a></li><li><a href="/en-US/docs/Learn_web_development/Changelog">Changelog</a></li></ol></div></div><section class="place side"></section></nav></aside><div class="toc-container"><aside class="toc"><nav><div class="document-toc-container"><section class="document-toc"><header><h2 class="document-toc-heading">In this article</h2></header><ul class="document-toc-list"><li class="document-toc-item "><a class="document-toc-link" href="#object_basics">Object basics</a></li><li class="document-toc-item "><a class="document-toc-link" href="#dot_notation">Dot notation</a></li><li class="document-toc-item "><a class="document-toc-link" href="#bracket_notation">Bracket notation</a></li><li class="document-toc-item "><a class="document-toc-link" href="#setting_object_members">Setting object members</a></li><li class="document-toc-item "><a class="document-toc-link" href="#what_is_this">What is "this"?</a></li><li class="document-toc-item "><a class="document-toc-link" href="#introducing_constructors">Introducing constructors</a></li><li class="document-toc-item "><a class="document-toc-link" href="#youve_been_using_objects_all_along">You've been using objects all along</a></li><li class="document-toc-item "><a class="document-toc-link" href="#test_your_skills!">Test your skills!</a></li><li class="document-toc-item "><a class="document-toc-link" href="#summary">Summary</a></li></ul></section></div></nav></aside><section class="place side"></section></div></div><main id="content" class="main-content "><article class="main-page-content" lang="en-US"><header><h1>JavaScript object basics</h1></header><div class="section-content"><ul class="prev-next"><li><a class="button secondary" href="/en-US/docs/Learn_web_development/Core/Scripting/Image_gallery"><span class="button-wrap"> Previous </span></a></li><li><a class="button secondary" href="/en-US/docs/Learn_web_development/Core/Scripting"><span class="button-wrap"> Overview: Dynamic scripting with JavaScript</span></a></li><li><a class="button secondary" href="/en-US/docs/Learn_web_development/Core/Scripting/DOM_scripting"><span class="button-wrap"> Next </span></a></li></ul> <p>In this article, we'll look at fundamental JavaScript object syntax, and revisit some JavaScript features that we've already seen earlier in the course, reiterating the fact that many of the features you've already dealt with are objects.</p> <figure class="table-container"><table> <tbody> <tr> <th scope="row">Prerequisites:</th> <td>An understanding of <a href="/en-US/docs/Learn_web_development/Core/Structuring_content">HTML</a> and the <a href="/en-US/docs/Learn_web_development/Core/Styling_basics">fundamentals of CSS</a>, familiarity with JavaScript basics as covered in previous lessons.</td> </tr> <tr> <th scope="row">Learning outcomes:</th> <td> <ul> <li>Understand that in JavaScript most things are objects, and you've probably used objects every time you've touched JavaScript.</li> <li>Basic syntax: Object literals, properties and methods, nesting objects and arrays in objects.</li> <li>Using constructors to create a new object.</li> <li>Object scope, and <code>this</code>.</li> <li>Accessing properties and methods — bracket and dot syntax.</li> <ul> </ul></ul></td> </tr> </tbody> </table></figure></div><section aria-labelledby="object_basics"><h2 id="object_basics"><a href="#object_basics">Object basics</a></h2><div class="section-content"><p>An object is a collection of related data and/or functionality. These usually consist of several variables and functions (which are called properties and methods when they are inside objects). Let's work through an example to understand what they look like.</p> <p>To begin with, make a local copy of our <a href="https://github.com/mdn/learning-area/blob/main/javascript/oojs/introduction/oojs.html" class="external" target="_blank">oojs.html</a> file. This contains very little — a <a href="/en-US/docs/Web/HTML/Element/script"><code><script></code></a> element for us to write our source code into. We'll use this as a basis for exploring basic object syntax. While working with this example you should have your <a href="/en-US/docs/Learn_web_development/Howto/Tools_and_setup/What_are_browser_developer_tools#the_javascript_console">developer tools JavaScript console</a> open and ready to type in some commands.</p> <p>As with many things in JavaScript, creating an object often begins with defining and initializing a variable. Try entering the following line below the JavaScript code that's already in your file, then saving and refreshing:</p> <div class="code-example"><div class="example-header"><span class="language-name">js</span></div><pre class="brush: js notranslate"><code>const person = {}; </code></pre></div> <p>Now open your browser's <a href="/en-US/docs/Learn_web_development/Howto/Tools_and_setup/What_are_browser_developer_tools#the_javascript_console">JavaScript console</a>, enter <code>person</code> into it, and press <kbd>Enter</kbd>/<kbd>Return</kbd>. You should get a result similar to one of the below lines:</p> <pre class="brush: plain notranslate">[object Object] Object { } { } </pre> <p>Congratulations, you've just created your first object. Job done! But this is an empty object, so we can't really do much with it. Let's update the JavaScript object in our file to look like this:</p> <div class="code-example"><div class="example-header"><span class="language-name">js</span></div><pre class="brush: js notranslate"><code>const person = { name: ["Bob", "Smith"], age: 32, bio: function () { console.log(`${this.name[0]} ${this.name[1]} is ${this.age} years old.`); }, introduceSelf: function () { console.log(`Hi! I'm ${this.name[0]}.`); }, }; </code></pre></div> <p>After saving and refreshing, try entering some of the following into the JavaScript console on your browser devtools:</p> <div class="code-example"><div class="example-header"><span class="language-name">js</span></div><pre class="brush: js notranslate"><code>person.name; person.name[0]; person.age; person.bio(); // "Bob Smith is 32 years old." person.introduceSelf(); // "Hi! I'm Bob." </code></pre></div> <p>You have now got some data and functionality inside your object, and are now able to access them with some nice simple syntax!</p> <p>So what is going on here? Well, an object is made up of multiple members, each of which has a name (e.g. <code>name</code> and <code>age</code> above), and a value (e.g. <code>['Bob', 'Smith']</code> and <code>32</code>). Each name/value pair must be separated by a comma, and the name and value in each case are separated by a colon. The syntax always follows this pattern:</p> <div class="code-example"><div class="example-header"><span class="language-name">js</span></div><pre class="brush: js notranslate"><code>const objectName = { member1Name: member1Value, member2Name: member2Value, member3Name: member3Value, }; </code></pre></div> <p>The value of an object member can be pretty much anything — in our person object we've got a number, an array, and two functions. The first two items are data items, and are referred to as the object's <strong>properties</strong>. The last two items are functions that allow the object to do something with that data, and are referred to as the object's <strong>methods</strong>.</p> <p>When the object's members are functions there's a simpler syntax. Instead of <code>bio: function ()</code> we can write <code>bio()</code>. Like this:</p> <div class="code-example"><div class="example-header"><span class="language-name">js</span></div><pre class="brush: js notranslate"><code>const person = { name: ["Bob", "Smith"], age: 32, bio() { console.log(`${this.name[0]} ${this.name[1]} is ${this.age} years old.`); }, introduceSelf() { console.log(`Hi! I'm ${this.name[0]}.`); }, }; </code></pre></div> <p>From now on, we'll use this shorter syntax.</p> <p>An object like this is referred to as an <strong>object literal</strong> — we've literally written out the object contents as we've come to create it. This is different compared to objects instantiated from classes, which we'll look at later on.</p> <p>It is very common to create an object using an object literal when you want to transfer a series of structured, related data items in some manner, for example sending a request to the server to be put into a database. Sending a single object is much more efficient than sending several items individually, and it is easier to work with than an array, when you want to identify individual items by name.</p></div></section><section aria-labelledby="dot_notation"><h2 id="dot_notation"><a href="#dot_notation">Dot notation</a></h2><div class="section-content"><p>Above, you accessed the object's properties and methods using <strong>dot notation</strong>. The object name (person) acts as the <strong>namespace</strong> — it must be entered first to access anything inside the object. Next you write a dot, then the item you want to access — this can be the name of a simple property, an item of an array property, or a call to one of the object's methods, for example:</p> <div class="code-example"><div class="example-header"><span class="language-name">js</span></div><pre class="brush: js notranslate"><code>person.age; person.bio(); </code></pre></div></div></section><section aria-labelledby="objects_as_object_properties"><h3 id="objects_as_object_properties"><a href="#objects_as_object_properties">Objects as object properties</a></h3><div class="section-content"><p>An object property can itself be an object. For example, try changing the <code>name</code> member from</p> <div class="code-example"><div class="example-header"><span class="language-name">js</span></div><pre class="brush: js notranslate"><code>const person = { name: ["Bob", "Smith"], }; </code></pre></div> <p>to</p> <div class="code-example"><div class="example-header"><span class="language-name">js</span></div><pre class="brush: js notranslate"><code>const person = { name: { first: "Bob", last: "Smith", }, // … }; </code></pre></div> <p>To access these items you just need to chain the extra step onto the end with another dot. Try these in the JS console:</p> <div class="code-example"><div class="example-header"><span class="language-name">js</span></div><pre class="brush: js notranslate"><code>person.name.first; person.name.last; </code></pre></div> <p>If you do this, you'll also need to go through your method code and change any instances of</p> <div class="code-example"><div class="example-header"><span class="language-name">js</span></div><pre class="brush: js notranslate"><code>name[0]; name[1]; </code></pre></div> <p>to</p> <div class="code-example"><div class="example-header"><span class="language-name">js</span></div><pre class="brush: js notranslate"><code>name.first; name.last; </code></pre></div> <p>Otherwise, your methods will no longer work.</p></div></section><section aria-labelledby="bracket_notation"><h2 id="bracket_notation"><a href="#bracket_notation">Bracket notation</a></h2><div class="section-content"><p>Bracket notation provides an alternative way to access object properties. Instead of using <a href="#dot_notation">dot notation</a> like this:</p> <div class="code-example"><div class="example-header"><span class="language-name">js</span></div><pre class="brush: js notranslate"><code>person.age; person.name.first; </code></pre></div> <p>You can instead use square brackets:</p> <div class="code-example"><div class="example-header"><span class="language-name">js</span></div><pre class="brush: js notranslate"><code>person["age"]; person["name"]["first"]; </code></pre></div> <p>This looks very similar to how you access the items in an array, and it is basically the same thing — instead of using an index number to select an item, you are using the name associated with each member's value. It is no wonder that objects are sometimes called <strong>associative arrays</strong> — they map strings to values in the same way that arrays map numbers to values.</p> <p>Dot notation is generally preferred over bracket notation because it is more succinct and easier to read. However there are some cases where you have to use square brackets. For example, if an object property name is held in a variable, then you can't use dot notation to access the value, but you can access the value using bracket notation.</p> <p>In the example below, the <code>logProperty()</code> function can use <code>person[propertyName]</code> to retrieve the value of the property named in <code>propertyName</code>.</p> <div class="code-example"><div class="example-header"><span class="language-name">js</span></div><pre class="brush: js notranslate"><code>const person = { name: ["Bob", "Smith"], age: 32, }; function logProperty(propertyName) { console.log(person[propertyName]); } logProperty("name"); // ["Bob", "Smith"] logProperty("age"); // 32 </code></pre></div></div></section><section aria-labelledby="setting_object_members"><h2 id="setting_object_members"><a href="#setting_object_members">Setting object members</a></h2><div class="section-content"><p>So far we've only looked at retrieving (or <strong>getting</strong>) object members — you can also <strong>set</strong> (update) the value of object members by declaring the member you want to set (using dot or bracket notation), like this:</p> <div class="code-example"><div class="example-header"><span class="language-name">js</span></div><pre class="brush: js notranslate"><code>person.age = 45; person["name"]["last"] = "Cratchit"; </code></pre></div> <p>Try entering the above lines, and then getting the members again to see how they've changed, like so:</p> <div class="code-example"><div class="example-header"><span class="language-name">js</span></div><pre class="brush: js notranslate"><code>person.age; person["name"]["last"]; </code></pre></div> <p>Setting members doesn't just stop at updating the values of existing properties and methods; you can also create completely new members. Try these in the JS console:</p> <div class="code-example"><div class="example-header"><span class="language-name">js</span></div><pre class="brush: js notranslate"><code>person["eyes"] = "hazel"; person.farewell = function () { console.log("Bye everybody!"); }; </code></pre></div> <p>You can now test out your new members:</p> <div class="code-example"><div class="example-header"><span class="language-name">js</span></div><pre class="brush: js notranslate"><code>person["eyes"]; person.farewell(); // "Bye everybody!" </code></pre></div> <p>One useful aspect of bracket notation is that it can be used to set not only member values dynamically, but member names too. Let's say we wanted users to be able to store custom value types in their people data, by typing the member name and value into two text inputs. We could get those values like this:</p> <div class="code-example"><div class="example-header"><span class="language-name">js</span></div><pre class="brush: js notranslate"><code>const myDataName = nameInput.value; const myDataValue = nameValue.value; </code></pre></div> <p>We could then add this new member name and value to the <code>person</code> object like this:</p> <div class="code-example"><div class="example-header"><span class="language-name">js</span></div><pre class="brush: js notranslate"><code>person[myDataName] = myDataValue; </code></pre></div> <p>To test this, try adding the following lines into your code, just below the closing curly brace of the <code>person</code> object:</p> <div class="code-example"><div class="example-header"><span class="language-name">js</span></div><pre class="brush: js notranslate"><code>const myDataName = "height"; const myDataValue = "1.75m"; person[myDataName] = myDataValue; </code></pre></div> <p>Now try saving and refreshing, and entering the following into your text input:</p> <div class="code-example"><div class="example-header"><span class="language-name">js</span></div><pre class="brush: js notranslate"><code>person.height; </code></pre></div> <p>Adding a property to an object using the method above isn't possible with dot notation, which can only accept a literal member name, not a variable value pointing to a name.</p></div></section><section aria-labelledby="what_is_this"><h2 id="what_is_this"><a href="#what_is_this">What is "this"?</a></h2><div class="section-content"><p>You may have noticed something slightly strange in our methods. Look at this one for example:</p> <div class="code-example"><div class="example-header"><span class="language-name">js</span></div><pre class="brush: js notranslate"><code>introduceSelf() { console.log(`Hi! I'm ${this.name[0]}.`); } </code></pre></div> <p>You are probably wondering what "this" is. The <code>this</code> keyword typically refers to the current object the code is being executed in. In the context of an object method, <code>this</code> refers to the object that the method was called on.</p> <p>Let's illustrate what we mean with a simplified pair of person objects:</p> <div class="code-example"><div class="example-header"><span class="language-name">js</span></div><pre class="brush: js notranslate"><code>const person1 = { name: "Chris", introduceSelf() { console.log(`Hi! I'm ${this.name}.`); }, }; const person2 = { name: "Deepti", introduceSelf() { console.log(`Hi! I'm ${this.name}.`); }, }; </code></pre></div> <p>In this case, <code>person1.introduceSelf()</code> outputs "Hi! I'm Chris."; <code>person2.introduceSelf()</code> outputs "Hi! I'm Deepti." This happens because when the method is called, <code>this</code> refers to the object on which the method is called, which allows the same method definition to work for multiple objects.</p> <p>This isn't hugely useful when you are writing out object literals by hand, as using the object's name (<code>person1</code> and <code>person2</code>) leads to the exact same result, but it will be essential when we start using <strong>constructors</strong> to create more than one object from a single object definition, and that's the subject of the next section.</p></div></section><section aria-labelledby="introducing_constructors"><h2 id="introducing_constructors"><a href="#introducing_constructors">Introducing constructors</a></h2><div class="section-content"><p>Using object literals is fine when you only need to create one object, but if you have to create more than one, as in the previous section, they're seriously inadequate. We have to write out the same code for every object we create, and if we want to change some properties of the object - like adding a <code>height</code> property - then we have to remember to update every object.</p> <p>We would like a way to define the "shape" of an object — the set of methods and the properties it can have — and then create as many objects as we like, just updating the values for the properties that are different.</p> <p>The first version of this is just a function:</p> <div class="code-example"><div class="example-header"><span class="language-name">js</span></div><pre class="brush: js notranslate"><code>function createPerson(name) { const obj = {}; obj.name = name; obj.introduceSelf = function () { console.log(`Hi! I'm ${this.name}.`); }; return obj; } </code></pre></div> <p>This function creates and returns a new object each time we call it. The object will have two members:</p> <ul> <li>a property <code>name</code></li> <li>a method <code>introduceSelf()</code>.</li> </ul> <p>Note that <code>createPerson()</code> takes a parameter <code>name</code> to set the value of the <code>name</code> property, but the value of the <code>introduceSelf()</code> method will be the same for all objects created using this function. This is a very common pattern for creating objects.</p> <p>Now we can create as many objects as we like, reusing the definition:</p> <div class="code-example"><div class="example-header"><span class="language-name">js</span></div><pre class="brush: js notranslate"><code>const salva = createPerson("Salva"); salva.introduceSelf(); // "Hi! I'm Salva." const frankie = createPerson("Frankie"); frankie.introduceSelf(); // "Hi! I'm Frankie." </code></pre></div> <p>This works fine but is a bit long-winded: we have to create an empty object, initialize it, and return it. A better way is to use a <strong>constructor</strong>. A constructor is just a function called using the <a href="/en-US/docs/Web/JavaScript/Reference/Operators/new"><code>new</code></a> keyword. When you call a constructor, it will:</p> <ul> <li>create a new object</li> <li>bind <code>this</code> to the new object, so you can refer to <code>this</code> in your constructor code</li> <li>run the code in the constructor</li> <li>return the new object.</li> </ul> <p>Constructors, by convention, start with a capital letter and are named for the type of object they create. So we could rewrite our example like this:</p> <div class="code-example"><div class="example-header"><span class="language-name">js</span></div><pre class="brush: js notranslate"><code>function Person(name) { this.name = name; this.introduceSelf = function () { console.log(`Hi! I'm ${this.name}.`); }; } </code></pre></div> <p>To call <code>Person()</code> as a constructor, we use <code>new</code>:</p> <div class="code-example"><div class="example-header"><span class="language-name">js</span></div><pre class="brush: js notranslate"><code>const salva = new Person("Salva"); salva.introduceSelf(); // "Hi! I'm Salva." const frankie = new Person("Frankie"); frankie.introduceSelf(); // "Hi! I'm Frankie." </code></pre></div></div></section><section aria-labelledby="youve_been_using_objects_all_along"><h2 id="youve_been_using_objects_all_along"><a href="#youve_been_using_objects_all_along">You've been using objects all along</a></h2><div class="section-content"><p>As you've been going through these examples, you have probably been thinking that the dot notation you've been using is very familiar. That's because you've been using it throughout the course! Every time we've been working through an example that uses a built-in browser API or JavaScript object, we've been using objects, because such features are built using exactly the same kind of object structures that we've been looking at here, albeit more complex ones than in our own basic custom examples.</p> <p>So when you used string methods like:</p> <div class="code-example"><div class="example-header"><span class="language-name">js</span></div><pre class="brush: js notranslate"><code>myString.split(","); </code></pre></div> <p>You were using a method available on a <a href="/en-US/docs/Web/JavaScript/Reference/Global_Objects/String"><code>String</code></a> object. Every time you create a string in your code, that string is automatically created as an instance of <code>String</code>, and therefore has several common methods and properties available on it.</p> <p>When you accessed the document object model using lines like this:</p> <div class="code-example"><div class="example-header"><span class="language-name">js</span></div><pre class="brush: js notranslate"><code>const myDiv = document.createElement("div"); const myVideo = document.querySelector("video"); </code></pre></div> <p>You were using methods available on a <a href="/en-US/docs/Web/API/Document"><code>Document</code></a> object. For each webpage loaded, an instance of <code>Document</code> is created, called <code>document</code>, which represents the entire page's structure, content, and other features such as its URL. Again, this means that it has several common methods and properties available on it.</p> <p>The same is true of pretty much any other built-in object or API you've been using — <a href="/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array"><code>Array</code></a>, <a href="/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math"><code>Math</code></a>, and so on.</p> <p>Note that built in objects and APIs don't always create object instances automatically. As an example, the <a href="/en-US/docs/Web/API/Notifications_API">Notifications API</a> — which allows modern browsers to fire system notifications — requires you to instantiate a new object instance using the constructor for each notification you want to fire. Try entering the following into your JavaScript console:</p> <div class="code-example"><div class="example-header"><span class="language-name">js</span></div><pre class="brush: js notranslate"><code>const myNotification = new Notification("Hello!"); </code></pre></div></div></section><section aria-labelledby="test_your_skills!"><h2 id="test_your_skills!"><a href="#test_your_skills!">Test your skills!</a></h2><div class="section-content"><p>You've reached the end of this article, but can you remember the most important information? You can find some further tests to verify that you've retained this information before you move on — see <a href="/en-US/docs/Learn_web_development/Core/Scripting/Test_your_skills:_Object_basics">Test your skills: Object basics</a>.</p></div></section><section aria-labelledby="summary"><h2 id="summary"><a href="#summary">Summary</a></h2><div class="section-content"><p>You should now have a good idea of how to work with objects in JavaScript — including creating your own simple objects. You should also appreciate that objects are very useful as structures for storing related data and functionality — if you tried to keep track of all the properties and methods in our <code>person</code> object as separate variables and functions, it would be inefficient and frustrating, and we'd run the risk of clashing with other variables and functions that have the same names. Objects let us keep the information safely locked away in their own package, out of harm's way.</p> <p>In the next article we'll look at <strong>DOM scripting</strong>, which unlocks a large amount of fundamental browser API functionality.</p> <ul class="prev-next"><li><a class="button secondary" href="/en-US/docs/Learn_web_development/Core/Scripting/Image_gallery"><span class="button-wrap"> Previous </span></a></li><li><a class="button secondary" href="/en-US/docs/Learn_web_development/Core/Scripting"><span class="button-wrap"> Overview: Dynamic scripting with JavaScript</span></a></li><li><a class="button secondary" href="/en-US/docs/Learn_web_development/Core/Scripting/DOM_scripting"><span class="button-wrap"> Next </span></a></li></ul></div></section></article><aside class="article-footer"><div class="article-footer-inner"><div class="svg-container"><svg xmlns="http://www.w3.org/2000/svg" width="162" height="162" viewBox="0 0 162 162" fill="none" role="none"><mask id="b" fill="#fff"><path d="M97.203 47.04c8.113-7.886 18.004-13.871 28.906-17.492a78 78 0 0 1 33.969-3.39c11.443 1.39 22.401 5.295 32.024 11.411s17.656 14.28 23.476 23.86c5.819 9.579 9.269 20.318 10.083 31.385a69.85 69.85 0 0 1-5.387 32.44c-4.358 10.272-11.115 19.443-19.747 26.801-8.632 7.359-18.908 12.709-30.034 15.637l-6.17-21.698c7.666-2.017 14.746-5.703 20.694-10.773 5.948-5.071 10.603-11.389 13.606-18.467a48.14 48.14 0 0 0 3.712-22.352c-.561-7.625-2.938-15.025-6.948-21.625s-9.544-12.226-16.175-16.44-14.181-6.904-22.065-7.863a53.75 53.75 0 0 0-23.405 2.336c-7.513 2.495-14.327 6.62-19.918 12.053z"></path></mask><path stroke="url(#a)" stroke-dasharray="6, 6" stroke-width="2" d="M97.203 47.04c8.113-7.886 18.004-13.871 28.906-17.492a78 78 0 0 1 33.969-3.39c11.443 1.39 22.401 5.295 32.024 11.411s17.656 14.28 23.476 23.86c5.819 9.579 9.269 20.318 10.083 31.385a69.85 69.85 0 0 1-5.387 32.44c-4.358 10.272-11.115 19.443-19.747 26.801-8.632 7.359-18.908 12.709-30.034 15.637l-6.17-21.698c7.666-2.017 14.746-5.703 20.694-10.773 5.948-5.071 10.603-11.389 13.606-18.467a48.14 48.14 0 0 0 3.712-22.352c-.561-7.625-2.938-15.025-6.948-21.625s-9.544-12.226-16.175-16.44-14.181-6.904-22.065-7.863a53.75 53.75 0 0 0-23.405 2.336c-7.513 2.495-14.327 6.62-19.918 12.053z" mask="url(#b)" style="stroke:url(#a)" transform="translate(-63.992 -25.587)"></path><ellipse cx="8.066" cy="111.597" fill="var(--background-tertiary)" rx="53.677" ry="53.699" transform="matrix(.71707 -.697 .7243 .6895 0 0)"></ellipse><g clip-path="url(#c)" transform="translate(-63.992 -25.587)"><path fill="#9abff5" d="m144.256 137.379 32.906 12.434a4.41 4.41 0 0 1 2.559 5.667l-9.326 24.679a4.41 4.41 0 0 1-5.667 2.559l-8.226-3.108-2.332 6.17c-.466 1.233-.375 1.883-1.609 1.417l-2.253-.527c-.411-.155-.95-.594-1.206-1.161l-4.734-10.484-12.545-4.741a4.41 4.41 0 0 1-2.559-5.667l9.325-24.679a4.41 4.41 0 0 1 5.667-2.559m9.961 29.617 8.227 3.108 3.264-8.638-.498-6.768-4.113-1.555.548 7.258-4.319-1.632zm-12.339-4.663 8.226 3.108 3.264-8.637-.498-6.769-4.113-1.554.548 7.257-4.319-1.632z"></path></g><g clip-path="url(#d)" transform="translate(-63.992 -25.587)"><path fill="#81b0f3" d="M135.35 60.136 86.67 41.654c-3.346-1.27-7.124.428-8.394 3.775L64.414 81.938c-1.27 3.347.428 7.125 3.774 8.395l12.17 4.62-3.465 9.128c-.693 1.826-1.432 2.457.394 3.15l3.014 1.625c.609.231 1.637.274 2.477-.104l15.53-6.983 18.56 7.047c3.346 1.27 7.124-.428 8.395-3.775l13.862-36.51c1.27-3.346-.428-7.124-3.775-8.395M95.261 83.207l-12.17-4.62 4.852-12.779 7.19-7.017 6.085 2.31-7.725 7.51 6.389 2.426zm18.255 6.93-12.17-4.62 4.852-12.778 7.189-7.017 6.085 2.31-7.725 7.51 6.39 2.426z"></path></g><defs><clipPath id="c"><path fill="#fff" d="m198.638 146.586-65.056-24.583-24.583 65.057 65.056 24.582z"></path></clipPath><clipPath id="d"><path fill="#fff" d="m66.438 14.055 96.242 36.54-36.54 96.243-96.243-36.54z"></path></clipPath><linearGradient id="a" x1="97.203" x2="199.995" y1="47.04" y2="152.793" gradientUnits="userSpaceOnUse"><stop stop-color="#086DFC"></stop><stop offset="0.246" stop-color="#2C81FA"></stop><stop offset="0.516" stop-color="#5497F8"></stop><stop offset="0.821" stop-color="#80B0F6"></stop><stop offset="1" stop-color="#9ABFF5"></stop></linearGradient></defs></svg></div><h2>Help improve MDN</h2><fieldset class="feedback"><label>Was this page helpful to you?</label><div class="button-container"><button type="button" class="button primary has-icon yes"><span class="button-wrap"><span class="icon icon-thumbs-up "></span>Yes</span></button><button type="button" class="button primary has-icon no"><span class="button-wrap"><span class="icon icon-thumbs-down "></span>No</span></button></div></fieldset><a class="contribute" href="https://github.com/mdn/content/blob/main/CONTRIBUTING.md" title="This will take you to our contribution guidelines on GitHub." target="_blank" rel="noopener noreferrer">Learn how to contribute</a>.<p class="last-modified-date">This page was last modified on <time dateTime="2024-12-19T15:37:45.000Z">Dec 19, 2024</time> by <a href="/en-US/docs/Learn_web_development/Core/Scripting/Object_basics/contributors.txt" rel="nofollow">MDN contributors</a>.</p><div id="on-github" class="on-github"><a href="https://github.com/mdn/content/blob/main/files/en-us/learn_web_development/core/scripting/object_basics/index.md?plain=1" title="Folder: en-us/learn_web_development/core/scripting/object_basics (Opens in a new tab)" target="_blank" rel="noopener noreferrer">View this page on GitHub</a> • <a href="https://github.com/mdn/content/issues/new?template=page-report.yml&mdn-url=https%3A%2F%2Fdeveloper.mozilla.org%2Fen-US%2Fdocs%2FLearn_web_development%2FCore%2FScripting%2FObject_basics&metadata=%3C%21--+Do+not+make+changes+below+this+line+--%3E%0A%3Cdetails%3E%0A%3Csummary%3EPage+report+details%3C%2Fsummary%3E%0A%0A*+Folder%3A+%60en-us%2Flearn_web_development%2Fcore%2Fscripting%2Fobject_basics%60%0A*+MDN+URL%3A+https%3A%2F%2Fdeveloper.mozilla.org%2Fen-US%2Fdocs%2FLearn_web_development%2FCore%2FScripting%2FObject_basics%0A*+GitHub+URL%3A+https%3A%2F%2Fgithub.com%2Fmdn%2Fcontent%2Fblob%2Fmain%2Ffiles%2Fen-us%2Flearn_web_development%2Fcore%2Fscripting%2Fobject_basics%2Findex.md%0A*+Last+commit%3A+https%3A%2F%2Fgithub.com%2Fmdn%2Fcontent%2Fcommit%2F5b20f5f4265f988f80f513db0e4b35c7e0cd70dc%0A*+Document+last+modified%3A+2024-12-19T15%3A37%3A45.000Z%0A%0A%3C%2Fdetails%3E" title="This will take you to GitHub to file a new issue." target="_blank" rel="noopener noreferrer">Report a problem with this content</a></div></div></aside></main></div></div><footer id="nav-footer" class="page-footer"><div class="page-footer-grid"><div class="page-footer-logo-col"><a href="/" class="mdn-footer-logo" aria-label="MDN homepage"><svg width="48" height="17" viewBox="0 0 48 17" fill="none" xmlns="http://www.w3.org/2000/svg"><title id="mdn-footer-logo-svg">MDN logo</title><path d="M20.04 16.512H15.504V10.416C15.504 9.488 15.344 8.824 15.024 8.424C14.72 8.024 14.264 7.824 13.656 7.824C12.92 7.824 12.384 8.064 12.048 8.544C11.728 9.024 11.568 9.64 11.568 10.392V14.184H13.008V16.512H8.472V10.416C8.472 9.488 8.312 8.824 7.992 8.424C7.688 8.024 7.232 7.824 6.624 7.824C5.872 7.824 5.336 8.064 5.016 8.544C4.696 9.024 4.536 9.64 4.536 10.392V14.184H6.6V16.512H0V14.184H1.44V8.04H0.024V5.688H4.536V7.32C5.224 6.088 6.32 5.472 7.824 5.472C8.608 5.472 9.328 5.664 9.984 6.048C10.64 6.432 11.096 7.016 11.352 7.8C11.992 6.248 13.168 5.472 14.88 5.472C15.856 5.472 16.72 5.776 17.472 6.384C18.224 6.992 18.6 7.936 18.6 9.216V14.184H20.04V16.512Z" fill="currentColor"></path><path d="M33.6714 16.512H29.1354V14.496C28.8314 15.12 28.3834 15.656 27.7914 16.104C27.1994 16.536 26.4154 16.752 25.4394 16.752C24.0154 16.752 22.8954 16.264 22.0794 15.288C21.2634 14.312 20.8554 12.984 20.8554 11.304C20.8554 9.688 21.2554 8.312 22.0554 7.176C22.8554 6.04 24.0634 5.472 25.6794 5.472C26.5594 5.472 27.2794 5.648 27.8394 6C28.3994 6.352 28.8314 6.8 29.1354 7.344V2.352H26.9754V0H32.2314V14.184H33.6714V16.512ZM29.1354 11.04V10.776C29.1354 9.88 28.8954 9.184 28.4154 8.688C27.9514 8.176 27.3674 7.92 26.6634 7.92C25.9754 7.92 25.3674 8.176 24.8394 8.688C24.3274 9.2 24.0714 10.008 24.0714 11.112C24.0714 12.152 24.3114 12.944 24.7914 13.488C25.2714 14.032 25.8394 14.304 26.4954 14.304C27.3114 14.304 27.9514 13.96 28.4154 13.272C28.8954 12.584 29.1354 11.84 29.1354 11.04Z" fill="currentColor"></path><path d="M47.9589 16.512H41.9829V14.184H43.4229V10.416C43.4229 9.488 43.2629 8.824 42.9429 8.424C42.6389 8.024 42.1829 7.824 41.5749 7.824C40.8389 7.824 40.2709 8.056 39.8709 8.52C39.4709 8.968 39.2629 9.56 39.2469 10.296V14.184H40.6869V16.512H34.7109V14.184H36.1509V8.04H34.5909V5.688H39.2469V7.344C39.9669 6.096 41.1269 5.472 42.7269 5.472C43.7509 5.472 44.6389 5.776 45.3909 6.384C46.1429 6.992 46.5189 7.936 46.5189 9.216V14.184H47.9589V16.512Z" fill="currentColor"></path></svg></a><p>Your blueprint for a better internet.</p><ul class="social-icons"><li><a href="https://mastodon.social/@mdn" target="_blank" rel="me noopener noreferrer"><span class="icon icon-mastodon"></span><span class="visually-hidden">MDN on Mastodon</span></a></li><li><a href="https://twitter.com/mozdevnet" target="_blank" rel="noopener noreferrer"><span class="icon icon-twitter-x"></span><span class="visually-hidden">MDN on X (formerly Twitter)</span></a></li><li><a href="https://github.com/mdn/" target="_blank" rel="noopener noreferrer"><span class="icon icon-github-mark-small"></span><span class="visually-hidden">MDN on GitHub</span></a></li><li><a href="/en-US/blog/rss.xml" target="_blank"><span class="icon icon-feed"></span><span class="visually-hidden">MDN Blog RSS Feed</span></a></li></ul></div><div class="page-footer-nav-col-1"><h2 class="footer-nav-heading">MDN</h2><ul class="footer-nav-list"><li class="footer-nav-item"><a href="/en-US/about">About</a></li><li class="footer-nav-item"><a href="/en-US/blog/">Blog</a></li><li class="footer-nav-item"><a href="https://www.mozilla.org/en-US/careers/listings/?team=ProdOps" target="_blank" rel="noopener noreferrer">Careers</a></li><li class="footer-nav-item"><a href="/en-US/advertising">Advertise with us</a></li></ul></div><div class="page-footer-nav-col-2"><h2 class="footer-nav-heading">Support</h2><ul class="footer-nav-list"><li class="footer-nav-item"><a class="footer-nav-link" href="https://support.mozilla.org/products/mdn-plus">Product help</a></li><li class="footer-nav-item"><a class="footer-nav-link" href="/en-US/docs/MDN/Community/Issues">Report an issue</a></li></ul></div><div class="page-footer-nav-col-3"><h2 class="footer-nav-heading">Our communities</h2><ul class="footer-nav-list"><li class="footer-nav-item"><a class="footer-nav-link" href="/en-US/community">MDN Community</a></li><li class="footer-nav-item"><a class="footer-nav-link" href="https://discourse.mozilla.org/c/mdn/236" target="_blank" rel="noopener noreferrer">MDN Forum</a></li><li class="footer-nav-item"><a class="footer-nav-link" href="/discord" target="_blank" rel="noopener noreferrer">MDN Chat</a></li></ul></div><div class="page-footer-nav-col-4"><h2 class="footer-nav-heading">Developers</h2><ul class="footer-nav-list"><li class="footer-nav-item"><a class="footer-nav-link" href="/en-US/docs/Web">Web Technologies</a></li><li class="footer-nav-item"><a class="footer-nav-link" href="/en-US/docs/Learn">Learn Web Development</a></li><li class="footer-nav-item"><a class="footer-nav-link" href="/en-US/plus">MDN Plus</a></li><li class="footer-nav-item"><a href="https://hacks.mozilla.org/" target="_blank" rel="noopener noreferrer">Hacks Blog</a></li></ul></div><div class="page-footer-moz"><a href="https://www.mozilla.org/" class="footer-moz-logo-link" target="_blank" rel="noopener noreferrer"><svg xmlns="http://www.w3.org/2000/svg" width="137" height="32" fill="none" viewBox="0 0 267.431 62.607"><path fill="currentColor" d="m13.913 23.056 5.33 25.356h2.195l5.33-25.356h14.267v38.976h-7.578V29.694h-2.194l-7.264 32.337h-7.343L9.418 29.694H7.223v32.337H-.354V23.056Zm47.137 9.123c9.12 0 14.423 5.385 14.423 15.214s-5.33 15.214-14.423 15.214c-9.12 0-14.423-5.385-14.423-15.214 0-9.855 5.304-15.214 14.423-15.214m0 24.363c4.285 0 6.428-2.196 6.428-7.032v-4.287c0-4.836-2.143-7.032-6.428-7.032s-6.428 2.196-6.428 7.032v4.287c0 4.836 2.143 7.032 6.428 7.032m18.473-.157 15.47-18.01h-15.26v-5.647h24.352v5.646L88.616 56.385h15.704v5.646H79.523Zm29.318-23.657h11.183V62.03h-7.578V38.375h-3.632v-5.646zm3.605-9.672h7.578v5.646h-7.578zm13.17 0h11.21v38.976h-7.578v-33.33h-3.632zm16.801 0H153.6v38.976h-7.577v-33.33h-3.632v-5.646zm29.03 9.123c4.442 0 7.394 2.143 8.231 5.881h2.194v-5.332h9.276v5.646h-3.632v18.011h3.632v5.646h-4.442c-3.135 0-4.834-1.699-4.834-4.836V56.7h-2.194c-.81 3.738-3.789 5.881-8.23 5.881-6.978 0-11.916-5.829-11.916-15.214 0-9.384 4.938-15.187 11.915-15.187m2.3 24.363c4.284 0 6.192-2.196 6.192-7.032v-4.287c0-4.836-1.908-7.032-6.193-7.032-4.18 0-6.193 2.196-6.193 7.032v4.287c0 4.836 2.012 7.032 6.193 7.032m48.34 5.489h-7.577V0h7.577zm6.585-29.643h32.165v-2.196l-21.295-7.634v-6.143l21.295-7.633V6.588h-25.345V0h32.165v12.522l-17.35 5.881V20.6l17.35 5.882v12.521h-38.985zm0-25.801h6.794v6.796h-6.794z"></path></svg></a><ul class="footer-moz-list"><li class="footer-moz-item"><a href="https://www.mozilla.org/privacy/websites/" class="footer-moz-link" target="_blank" rel="noopener noreferrer">Website Privacy Notice</a></li><li class="footer-moz-item"><a href="https://www.mozilla.org/privacy/websites/#cookies" class="footer-moz-link" target="_blank" rel="noopener noreferrer">Cookies</a></li><li class="footer-moz-item"><a href="https://www.mozilla.org/about/legal/terms/mozilla" class="footer-moz-link" target="_blank" rel="noopener noreferrer">Legal</a></li><li class="footer-moz-item"><a href="https://www.mozilla.org/about/governance/policies/participation/" class="footer-moz-link" target="_blank" rel="noopener noreferrer">Community Participation Guidelines</a></li></ul></div><div class="page-footer-legal"><p id="license" class="page-footer-legal-text">Visit <a href="https://www.mozilla.org" target="_blank" rel="noopener noreferrer">Mozilla Corporation’s</a> not-for-profit parent, the <a target="_blank" rel="noopener noreferrer" href="https://foundation.mozilla.org/">Mozilla Foundation</a>.<br/>Portions of this content are ©1998–2025 by individual mozilla.org contributors. Content available under <a href="/en-US/docs/MDN/Writing_guidelines/Attrib_copyright_license">a Creative Commons license</a>.</p></div></div></footer></div><script type="application/json" id="hydration">{"url":"/en-US/docs/Learn_web_development/Core/Scripting/Object_basics","doc":{"body":[{"type":"prose","value":{"id":null,"title":null,"isH3":false,"content":"<ul class=\"prev-next\"><li><a class=\"button secondary\" href=\"/en-US/docs/Learn_web_development/Core/Scripting/Image_gallery\"><span class=\"button-wrap\"> Previous </span></a></li><li><a class=\"button secondary\" href=\"/en-US/docs/Learn_web_development/Core/Scripting\"><span class=\"button-wrap\"> Overview: Dynamic scripting with JavaScript</span></a></li><li><a class=\"button secondary\" href=\"/en-US/docs/Learn_web_development/Core/Scripting/DOM_scripting\"><span class=\"button-wrap\"> Next </span></a></li></ul>\n<p>In this article, we'll look at fundamental JavaScript object syntax, and revisit some JavaScript features that we've already seen earlier in the course, reiterating the fact that many of the features you've already dealt with are objects.</p>\n<figure class=\"table-container\"><table>\n <tbody>\n <tr>\n <th scope=\"row\">Prerequisites:</th>\n <td>An understanding of <a href=\"/en-US/docs/Learn_web_development/Core/Structuring_content\">HTML</a> and the <a href=\"/en-US/docs/Learn_web_development/Core/Styling_basics\">fundamentals of CSS</a>, familiarity with JavaScript basics as covered in previous lessons.</td>\n </tr>\n <tr>\n <th scope=\"row\">Learning outcomes:</th>\n <td>\n <ul>\n <li>Understand that in JavaScript most things are objects, and you've probably used objects every time you've touched JavaScript.</li>\n <li>Basic syntax: Object literals, properties and methods, nesting objects and arrays in objects.</li>\n <li>Using constructors to create a new object.</li>\n <li>Object scope, and <code>this</code>.</li>\n <li>Accessing properties and methods — bracket and dot syntax.</li>\n <ul>\n </ul></ul></td>\n </tr>\n </tbody>\n</table></figure>"}},{"type":"prose","value":{"id":"object_basics","title":"Object basics","isH3":false,"content":"<p>An object is a collection of related data and/or functionality.\nThese usually consist of several variables and functions (which are called properties and methods when they are inside objects).\nLet's work through an example to understand what they look like.</p>\n<p>To begin with, make a local copy of our <a href=\"https://github.com/mdn/learning-area/blob/main/javascript/oojs/introduction/oojs.html\" class=\"external\" target=\"_blank\">oojs.html</a> file. This contains very little — a <a href=\"/en-US/docs/Web/HTML/Element/script\"><code><script></code></a> element for us to write our source code into. We'll use this as a basis for exploring basic object syntax. While working with this example you should have your <a href=\"/en-US/docs/Learn_web_development/Howto/Tools_and_setup/What_are_browser_developer_tools#the_javascript_console\">developer tools JavaScript console</a> open and ready to type in some commands.</p>\n<p>As with many things in JavaScript, creating an object often begins with defining and initializing a variable. Try entering the following line below the JavaScript code that's already in your file, then saving and refreshing:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">js</span></div><pre class=\"brush: js notranslate\"><code>const person = {};\n</code></pre></div>\n<p>Now open your browser's <a href=\"/en-US/docs/Learn_web_development/Howto/Tools_and_setup/What_are_browser_developer_tools#the_javascript_console\">JavaScript console</a>, enter <code>person</code> into it, and press <kbd>Enter</kbd>/<kbd>Return</kbd>. You should get a result similar to one of the below lines:</p>\n<pre class=\"brush: plain notranslate\">[object Object]\nObject { }\n{ }\n</pre>\n<p>Congratulations, you've just created your first object. Job done! But this is an empty object, so we can't really do much with it. Let's update the JavaScript object in our file to look like this:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">js</span></div><pre class=\"brush: js notranslate\"><code>const person = {\n name: [\"Bob\", \"Smith\"],\n age: 32,\n bio: function () {\n console.log(`${this.name[0]} ${this.name[1]} is ${this.age} years old.`);\n },\n introduceSelf: function () {\n console.log(`Hi! I'm ${this.name[0]}.`);\n },\n};\n</code></pre></div>\n<p>After saving and refreshing, try entering some of the following into the JavaScript console on your browser devtools:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">js</span></div><pre class=\"brush: js notranslate\"><code>person.name;\nperson.name[0];\nperson.age;\nperson.bio();\n// \"Bob Smith is 32 years old.\"\nperson.introduceSelf();\n// \"Hi! I'm Bob.\"\n</code></pre></div>\n<p>You have now got some data and functionality inside your object, and are now able to access them with some nice simple syntax!</p>\n<p>So what is going on here? Well, an object is made up of multiple members, each of which has a name (e.g. <code>name</code> and <code>age</code> above), and a value (e.g. <code>['Bob', 'Smith']</code> and <code>32</code>). Each name/value pair must be separated by a comma, and the name and value in each case are separated by a colon. The syntax always follows this pattern:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">js</span></div><pre class=\"brush: js notranslate\"><code>const objectName = {\n member1Name: member1Value,\n member2Name: member2Value,\n member3Name: member3Value,\n};\n</code></pre></div>\n<p>The value of an object member can be pretty much anything — in our person object we've got a number, an array, and two functions. The first two items are data items, and are referred to as the object's <strong>properties</strong>. The last two items are functions that allow the object to do something with that data, and are referred to as the object's <strong>methods</strong>.</p>\n<p>When the object's members are functions there's a simpler syntax. Instead of <code>bio: function ()</code> we can write <code>bio()</code>. Like this:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">js</span></div><pre class=\"brush: js notranslate\"><code>const person = {\n name: [\"Bob\", \"Smith\"],\n age: 32,\n bio() {\n console.log(`${this.name[0]} ${this.name[1]} is ${this.age} years old.`);\n },\n introduceSelf() {\n console.log(`Hi! I'm ${this.name[0]}.`);\n },\n};\n</code></pre></div>\n<p>From now on, we'll use this shorter syntax.</p>\n<p>An object like this is referred to as an <strong>object literal</strong> — we've literally written out the object contents as we've come to create it. This is different compared to objects instantiated from classes, which we'll look at later on.</p>\n<p>It is very common to create an object using an object literal when you want to transfer a series of structured, related data items in some manner, for example sending a request to the server to be put into a database. Sending a single object is much more efficient than sending several items individually, and it is easier to work with than an array, when you want to identify individual items by name.</p>"}},{"type":"prose","value":{"id":"dot_notation","title":"Dot notation","isH3":false,"content":"<p>Above, you accessed the object's properties and methods using <strong>dot notation</strong>. The object name (person) acts as the <strong>namespace</strong> — it must be entered first to access anything inside the object. Next you write a dot, then the item you want to access — this can be the name of a simple property, an item of an array property, or a call to one of the object's methods, for example:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">js</span></div><pre class=\"brush: js notranslate\"><code>person.age;\nperson.bio();\n</code></pre></div>"}},{"type":"prose","value":{"id":"objects_as_object_properties","title":"Objects as object properties","isH3":true,"content":"<p>An object property can itself be an object. For example, try changing the <code>name</code> member from</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">js</span></div><pre class=\"brush: js notranslate\"><code>const person = {\n name: [\"Bob\", \"Smith\"],\n};\n</code></pre></div>\n<p>to</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">js</span></div><pre class=\"brush: js notranslate\"><code>const person = {\n name: {\n first: \"Bob\",\n last: \"Smith\",\n },\n // …\n};\n</code></pre></div>\n<p>To access these items you just need to chain the extra step onto the end with another dot. Try these in the JS console:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">js</span></div><pre class=\"brush: js notranslate\"><code>person.name.first;\nperson.name.last;\n</code></pre></div>\n<p>If you do this, you'll also need to go through your method code and change any instances of</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">js</span></div><pre class=\"brush: js notranslate\"><code>name[0];\nname[1];\n</code></pre></div>\n<p>to</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">js</span></div><pre class=\"brush: js notranslate\"><code>name.first;\nname.last;\n</code></pre></div>\n<p>Otherwise, your methods will no longer work.</p>"}},{"type":"prose","value":{"id":"bracket_notation","title":"Bracket notation","isH3":false,"content":"<p>Bracket notation provides an alternative way to access object properties.\nInstead of using <a href=\"#dot_notation\">dot notation</a> like this:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">js</span></div><pre class=\"brush: js notranslate\"><code>person.age;\nperson.name.first;\n</code></pre></div>\n<p>You can instead use square brackets:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">js</span></div><pre class=\"brush: js notranslate\"><code>person[\"age\"];\nperson[\"name\"][\"first\"];\n</code></pre></div>\n<p>This looks very similar to how you access the items in an array, and it is basically the same thing — instead of using an index number to select an item, you are using the name associated with each member's value.\nIt is no wonder that objects are sometimes called <strong>associative arrays</strong> — they map strings to values in the same way that arrays map numbers to values.</p>\n<p>Dot notation is generally preferred over bracket notation because it is more succinct and easier to read.\nHowever there are some cases where you have to use square brackets.\nFor example, if an object property name is held in a variable, then you can't use dot notation to access the value, but you can access the value using bracket notation.</p>\n<p>In the example below, the <code>logProperty()</code> function can use <code>person[propertyName]</code> to retrieve the value of the property named in <code>propertyName</code>.</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">js</span></div><pre class=\"brush: js notranslate\"><code>const person = {\n name: [\"Bob\", \"Smith\"],\n age: 32,\n};\n\nfunction logProperty(propertyName) {\n console.log(person[propertyName]);\n}\n\nlogProperty(\"name\");\n// [\"Bob\", \"Smith\"]\nlogProperty(\"age\");\n// 32\n</code></pre></div>"}},{"type":"prose","value":{"id":"setting_object_members","title":"Setting object members","isH3":false,"content":"<p>So far we've only looked at retrieving (or <strong>getting</strong>) object members — you can also <strong>set</strong> (update) the value of object members by declaring the member you want to set (using dot or bracket notation), like this:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">js</span></div><pre class=\"brush: js notranslate\"><code>person.age = 45;\nperson[\"name\"][\"last\"] = \"Cratchit\";\n</code></pre></div>\n<p>Try entering the above lines, and then getting the members again to see how they've changed, like so:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">js</span></div><pre class=\"brush: js notranslate\"><code>person.age;\nperson[\"name\"][\"last\"];\n</code></pre></div>\n<p>Setting members doesn't just stop at updating the values of existing properties and methods; you can also create completely new members. Try these in the JS console:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">js</span></div><pre class=\"brush: js notranslate\"><code>person[\"eyes\"] = \"hazel\";\nperson.farewell = function () {\n console.log(\"Bye everybody!\");\n};\n</code></pre></div>\n<p>You can now test out your new members:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">js</span></div><pre class=\"brush: js notranslate\"><code>person[\"eyes\"];\nperson.farewell();\n// \"Bye everybody!\"\n</code></pre></div>\n<p>One useful aspect of bracket notation is that it can be used to set not only member values dynamically, but member names too. Let's say we wanted users to be able to store custom value types in their people data, by typing the member name and value into two text inputs. We could get those values like this:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">js</span></div><pre class=\"brush: js notranslate\"><code>const myDataName = nameInput.value;\nconst myDataValue = nameValue.value;\n</code></pre></div>\n<p>We could then add this new member name and value to the <code>person</code> object like this:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">js</span></div><pre class=\"brush: js notranslate\"><code>person[myDataName] = myDataValue;\n</code></pre></div>\n<p>To test this, try adding the following lines into your code, just below the closing curly brace of the <code>person</code> object:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">js</span></div><pre class=\"brush: js notranslate\"><code>const myDataName = \"height\";\nconst myDataValue = \"1.75m\";\nperson[myDataName] = myDataValue;\n</code></pre></div>\n<p>Now try saving and refreshing, and entering the following into your text input:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">js</span></div><pre class=\"brush: js notranslate\"><code>person.height;\n</code></pre></div>\n<p>Adding a property to an object using the method above isn't possible with dot notation, which can only accept a literal member name, not a variable value pointing to a name.</p>"}},{"type":"prose","value":{"id":"what_is_this","title":"What is \"this\"?","isH3":false,"content":"<p>You may have noticed something slightly strange in our methods. Look at this one for example:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">js</span></div><pre class=\"brush: js notranslate\"><code>introduceSelf() {\n console.log(`Hi! I'm ${this.name[0]}.`);\n}\n</code></pre></div>\n<p>You are probably wondering what \"this\" is. The <code>this</code> keyword typically refers to the current object the code is being executed in. In the context of an object method, <code>this</code> refers to the object that the method was called on.</p>\n<p>Let's illustrate what we mean with a simplified pair of person objects:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">js</span></div><pre class=\"brush: js notranslate\"><code>const person1 = {\n name: \"Chris\",\n introduceSelf() {\n console.log(`Hi! I'm ${this.name}.`);\n },\n};\n\nconst person2 = {\n name: \"Deepti\",\n introduceSelf() {\n console.log(`Hi! I'm ${this.name}.`);\n },\n};\n</code></pre></div>\n<p>In this case, <code>person1.introduceSelf()</code> outputs \"Hi! I'm Chris.\"; <code>person2.introduceSelf()</code> outputs \"Hi! I'm Deepti.\" This happens because when the method is called, <code>this</code> refers to the object on which the method is called, which allows the same method definition to work for multiple objects.</p>\n<p>This isn't hugely useful when you are writing out object literals by hand, as using the object's name (<code>person1</code> and <code>person2</code>) leads to the exact same result, but it will be essential when we start using <strong>constructors</strong> to create more than one object from a single object definition, and that's the subject of the next section.</p>"}},{"type":"prose","value":{"id":"introducing_constructors","title":"Introducing constructors","isH3":false,"content":"<p>Using object literals is fine when you only need to create one object, but if you have to create more than one, as in the previous section, they're seriously inadequate. We have to write out the same code for every object we create, and if we want to change some properties of the object - like adding a <code>height</code> property - then we have to remember to update every object.</p>\n<p>We would like a way to define the \"shape\" of an object — the set of methods and the properties it can have — and then create as many objects as we like, just updating the values for the properties that are different.</p>\n<p>The first version of this is just a function:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">js</span></div><pre class=\"brush: js notranslate\"><code>function createPerson(name) {\n const obj = {};\n obj.name = name;\n obj.introduceSelf = function () {\n console.log(`Hi! I'm ${this.name}.`);\n };\n return obj;\n}\n</code></pre></div>\n<p>This function creates and returns a new object each time we call it. The object will have two members:</p>\n<ul>\n<li>a property <code>name</code></li>\n<li>a method <code>introduceSelf()</code>.</li>\n</ul>\n<p>Note that <code>createPerson()</code> takes a parameter <code>name</code> to set the value of the <code>name</code> property, but the value of the <code>introduceSelf()</code> method will be the same for all objects created using this function. This is a very common pattern for creating objects.</p>\n<p>Now we can create as many objects as we like, reusing the definition:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">js</span></div><pre class=\"brush: js notranslate\"><code>const salva = createPerson(\"Salva\");\nsalva.introduceSelf();\n// \"Hi! I'm Salva.\"\n\nconst frankie = createPerson(\"Frankie\");\nfrankie.introduceSelf();\n// \"Hi! I'm Frankie.\"\n</code></pre></div>\n<p>This works fine but is a bit long-winded: we have to create an empty object, initialize it, and return it. A better way is to use a <strong>constructor</strong>. A constructor is just a function called using the <a href=\"/en-US/docs/Web/JavaScript/Reference/Operators/new\"><code>new</code></a> keyword. When you call a constructor, it will:</p>\n<ul>\n<li>create a new object</li>\n<li>bind <code>this</code> to the new object, so you can refer to <code>this</code> in your constructor code</li>\n<li>run the code in the constructor</li>\n<li>return the new object.</li>\n</ul>\n<p>Constructors, by convention, start with a capital letter and are named for the type of object they create. So we could rewrite our example like this:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">js</span></div><pre class=\"brush: js notranslate\"><code>function Person(name) {\n this.name = name;\n this.introduceSelf = function () {\n console.log(`Hi! I'm ${this.name}.`);\n };\n}\n</code></pre></div>\n<p>To call <code>Person()</code> as a constructor, we use <code>new</code>:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">js</span></div><pre class=\"brush: js notranslate\"><code>const salva = new Person(\"Salva\");\nsalva.introduceSelf();\n// \"Hi! I'm Salva.\"\n\nconst frankie = new Person(\"Frankie\");\nfrankie.introduceSelf();\n// \"Hi! I'm Frankie.\"\n</code></pre></div>"}},{"type":"prose","value":{"id":"youve_been_using_objects_all_along","title":"You've been using objects all along","isH3":false,"content":"<p>As you've been going through these examples, you have probably been thinking that the dot notation you've been using is very familiar. That's because you've been using it throughout the course! Every time we've been working through an example that uses a built-in browser API or JavaScript object, we've been using objects, because such features are built using exactly the same kind of object structures that we've been looking at here, albeit more complex ones than in our own basic custom examples.</p>\n<p>So when you used string methods like:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">js</span></div><pre class=\"brush: js notranslate\"><code>myString.split(\",\");\n</code></pre></div>\n<p>You were using a method available on a <a href=\"/en-US/docs/Web/JavaScript/Reference/Global_Objects/String\"><code>String</code></a> object. Every time you create a string in your code, that string is automatically created as an instance of <code>String</code>, and therefore has several common methods and properties available on it.</p>\n<p>When you accessed the document object model using lines like this:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">js</span></div><pre class=\"brush: js notranslate\"><code>const myDiv = document.createElement(\"div\");\nconst myVideo = document.querySelector(\"video\");\n</code></pre></div>\n<p>You were using methods available on a <a href=\"/en-US/docs/Web/API/Document\"><code>Document</code></a> object. For each webpage loaded, an instance of <code>Document</code> is created, called <code>document</code>, which represents the entire page's structure, content, and other features such as its URL. Again, this means that it has several common methods and properties available on it.</p>\n<p>The same is true of pretty much any other built-in object or API you've been using — <a href=\"/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array\"><code>Array</code></a>, <a href=\"/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math\"><code>Math</code></a>, and so on.</p>\n<p>Note that built in objects and APIs don't always create object instances automatically. As an example, the <a href=\"/en-US/docs/Web/API/Notifications_API\">Notifications API</a> — which allows modern browsers to fire system notifications — requires you to instantiate a new object instance using the constructor for each notification you want to fire. Try entering the following into your JavaScript console:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">js</span></div><pre class=\"brush: js notranslate\"><code>const myNotification = new Notification(\"Hello!\");\n</code></pre></div>"}},{"type":"prose","value":{"id":"test_your_skills!","title":"Test your skills!","isH3":false,"content":"<p>You've reached the end of this article, but can you remember the most important information? You can find some further tests to verify that you've retained this information before you move on — see <a href=\"/en-US/docs/Learn_web_development/Core/Scripting/Test_your_skills:_Object_basics\">Test your skills: Object basics</a>.</p>"}},{"type":"prose","value":{"id":"summary","title":"Summary","isH3":false,"content":"<p>You should now have a good idea of how to work with objects in JavaScript — including creating your own simple objects. You should also appreciate that objects are very useful as structures for storing related data and functionality — if you tried to keep track of all the properties and methods in our <code>person</code> object as separate variables and functions, it would be inefficient and frustrating, and we'd run the risk of clashing with other variables and functions that have the same names. Objects let us keep the information safely locked away in their own package, out of harm's way.</p>\n<p>In the next article we'll look at <strong>DOM scripting</strong>, which unlocks a large amount of fundamental browser API functionality.</p>\n<ul class=\"prev-next\"><li><a class=\"button secondary\" href=\"/en-US/docs/Learn_web_development/Core/Scripting/Image_gallery\"><span class=\"button-wrap\"> Previous </span></a></li><li><a class=\"button secondary\" href=\"/en-US/docs/Learn_web_development/Core/Scripting\"><span class=\"button-wrap\"> Overview: Dynamic scripting with JavaScript</span></a></li><li><a class=\"button secondary\" href=\"/en-US/docs/Learn_web_development/Core/Scripting/DOM_scripting\"><span class=\"button-wrap\"> Next </span></a></li></ul>"}}],"isActive":true,"isMarkdown":true,"isTranslated":false,"locale":"en-US","mdn_url":"/en-US/docs/Learn_web_development/Core/Scripting/Object_basics","modified":"2024-12-19T15:37:45.000Z","native":"English (US)","noIndexing":false,"other_translations":[{"locale":"de","title":"JavaScript-Objektgrundlagen","native":"Deutsch"},{"locale":"es","title":"Conceptos básicos de los objetos JavaScript","native":"Español"},{"locale":"fr","title":"Les bases de JavaScript, orienté objet","native":"Français"},{"locale":"ja","title":"JavaScript オブジェクトの基本","native":"日本語"},{"locale":"ko","title":"JavaScript 객체 기본","native":"한국어"},{"locale":"pt-BR","title":"O básico sobre objetos JavaScript","native":"Português (do Brasil)"},{"locale":"ru","title":"Основы объектов в JavaScript","native":"Русский"},{"locale":"zh-CN","title":"JavaScript 对象基础","native":"中文 (简体)"},{"locale":"zh-TW","title":"JavaScript 物件基礎概念","native":"正體中文 (繁體)"}],"pageTitle":"JavaScript object basics - Learn web development | MDN","parents":[{"uri":"/en-US/docs/Learn_web_development","title":"Learn"},{"uri":"/en-US/docs/Learn_web_development/Core","title":"Core learning modules"},{"uri":"/en-US/docs/Learn_web_development/Core/Scripting","title":"Dynamic scripting with JavaScript"},{"uri":"/en-US/docs/Learn_web_development/Core/Scripting/Object_basics","title":"JavaScript object basics"}],"popularity":null,"short_title":"JavaScript object basics","sidebarHTML":"<ol><li class=\"section\"><a href=\"/en-US/docs/Learn_web_development/Getting_started\">Getting started modules</a></li><li class=\"toggle\"><details><summary><a href=\"/en-US/docs/Learn_web_development/Getting_started/Environment_setup\">Environment setup</a></summary><ol><li><a href=\"/en-US/docs/Learn_web_development/Getting_started/Environment_setup/Installing_software\">Installing basic software</a></li><li><a href=\"/en-US/docs/Learn_web_development/Getting_started/Environment_setup/Browsing_the_web\">Browsing the web</a></li><li><a href=\"/en-US/docs/Learn_web_development/Getting_started/Environment_setup/Code_editors\">Code editors</a></li><li><a href=\"/en-US/docs/Learn_web_development/Getting_started/Environment_setup/Dealing_with_files\">Dealing with files</a></li><li><a href=\"/en-US/docs/Learn_web_development/Getting_started/Environment_setup/Command_line\">Command line crash course</a></li></ol></details></li><li class=\"toggle\"><details><summary><a href=\"/en-US/docs/Learn_web_development/Getting_started/Your_first_website\">Your first website</a></summary><ol><li><a href=\"/en-US/docs/Learn_web_development/Getting_started/Your_first_website/What_will_your_website_look_like\">What will your website look like?</a></li><li><a href=\"/en-US/docs/Learn_web_development/Getting_started/Your_first_website/Creating_the_content\">HTML: Creating the content</a></li><li><a href=\"/en-US/docs/Learn_web_development/Getting_started/Your_first_website/Styling_the_content\">CSS: Styling the content</a></li><li><a href=\"/en-US/docs/Learn_web_development/Getting_started/Your_first_website/Adding_interactivity\">JavaScript: Adding interactivity</a></li><li><a href=\"/en-US/docs/Learn_web_development/Getting_started/Your_first_website/Publishing_your_website\">Publishing your website</a></li></ol></details></li><li class=\"toggle\"><details><summary><a href=\"/en-US/docs/Learn_web_development/Getting_started/Web_standards\">Web standards</a></summary><ol><li><a href=\"/en-US/docs/Learn_web_development/Getting_started/Web_standards/How_the_web_works\">How the web works</a></li><li><a href=\"/en-US/docs/Learn_web_development/Getting_started/Web_standards/The_web_standards_model\">The web standards model</a></li><li><a href=\"/en-US/docs/Learn_web_development/Getting_started/Web_standards/How_browsers_load_websites\">How browsers load websites</a></li></ol></details></li><li class=\"toggle\"><details><summary><a href=\"/en-US/docs/Learn_web_development/Getting_started/Soft_skills\">Soft skills</a></summary><ol><li><a href=\"/en-US/docs/Learn_web_development/Getting_started/Soft_skills/Research_and_learning\">Research and learning</a></li><li><a href=\"/en-US/docs/Learn_web_development/Getting_started/Soft_skills/Collaboration_and_teamwork\">Collaboration and teamwork</a></li><li><a href=\"/en-US/docs/Learn_web_development/Getting_started/Soft_skills/Workflows_and_processes\">Workflows and processes</a></li><li><a href=\"/en-US/docs/Learn_web_development/Getting_started/Soft_skills/Job_interviews\">Succeeding in job interviews</a></li></ol></details></li><li class=\"section\"><a href=\"/en-US/docs/Learn_web_development/Core\">Core modules</a></li><li class=\"toggle\"><details><summary><a href=\"/en-US/docs/Learn_web_development/Core/Structuring_content\">Structuring content with HTML</a></summary><ol><li><a href=\"/en-US/docs/Learn_web_development/Core/Structuring_content/Basic_HTML_syntax\">Basic HTML syntax</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Structuring_content/Webpage_metadata\">What's in the head? Webpage metadata</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Structuring_content/Headings_and_paragraphs\">Headings and paragraphs in HTML</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Structuring_content/Emphasis_and_importance\">Emphasis and importance</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Structuring_content/Lists\">Lists</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Structuring_content/Structuring_documents\">Structuring documents</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Structuring_content/Advanced_text_features\">Advanced text features</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Structuring_content/Creating_links\">Creating links</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Structuring_content/Marking_up_a_letter\">Challenge: Marking up a letter</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Structuring_content/Structuring_a_page_of_content\">Challenge: Structuring a page of content</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Structuring_content/HTML_images\">HTML images</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Structuring_content/HTML_video_and_audio\">HTML video and audio</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Structuring_content/Mozilla_splash_page\">Challenge: Mozilla splash page</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Structuring_content/HTML_table_basics\">HTML table basics</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Structuring_content/Table_accessibility\">HTML table accessibility</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Structuring_content/Planet_data_table\">Challenge: Structuring a planet data table</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Structuring_content/HTML_forms\">Forms and buttons in HTML</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Structuring_content/Debugging_HTML\">Debugging HTML</a></li></ol></details></li><li class=\"toggle\"><details><summary><a href=\"/en-US/docs/Learn_web_development/Core/Styling_basics\">CSS styling basics</a></summary><ol><li><a href=\"/en-US/docs/Learn_web_development/Core/Styling_basics/What_is_CSS\">What is CSS?</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Styling_basics/Getting_started\">Getting started with CSS</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Styling_basics/Styling_a_bio_page\">Challenge: Styling a biography page</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Styling_basics/Basic_selectors\">Basic CSS selectors</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Styling_basics/Attribute_selectors\">Attribute selectors</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Styling_basics/Pseudo_classes_and_elements\">Pseudo-classes and pseudo-elements</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Styling_basics/Combinators\">Combinators</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Styling_basics/Box_model\">The box model</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Styling_basics/Handling_conflicts\">Handling conflicts</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Styling_basics/Values_and_units\">CSS values and units</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Styling_basics/Sizing\">Sizing items in CSS</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Styling_basics/Backgrounds_and_borders\">Backgrounds and borders</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Styling_basics/Overflow\">Overflowing content</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Styling_basics/Images_media_forms\">Images, media, and form elements</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Styling_basics/Tables\">Styling tables</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Styling_basics/Debugging_CSS\">Debugging CSS</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Styling_basics/Fundamental_CSS_comprehension\">Challenge: Fundamental CSS comprehension</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Styling_basics/Fancy_letterheaded_paper\">Challenge: Creating fancy letterheaded paper</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Styling_basics/Cool-looking_box\">Challenge: A cool-looking box</a></li></ol></details></li><li class=\"toggle\"><details><summary><a href=\"/en-US/docs/Learn_web_development/Core/Text_styling\">CSS text styling</a></summary><ol><li><a href=\"/en-US/docs/Learn_web_development/Core/Text_styling/Fundamentals\">Fundamental text and font styling</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Text_styling/Styling_lists\">Styling lists</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Text_styling/Styling_links\">Styling links</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Text_styling/Web_fonts\">Web fonts</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Text_styling/Typesetting_a_homepage\">Challenge: Typesetting a community school homepage</a></li></ol></details></li><li class=\"toggle\"><details><summary><a href=\"/en-US/docs/Learn_web_development/Core/CSS_layout\">CSS layout</a></summary><ol><li><a href=\"/en-US/docs/Learn_web_development/Core/CSS_layout/Introduction\">Introduction to CSS layout</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/CSS_layout/Floats\">Floats</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/CSS_layout/Positioning\">Positioning</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/CSS_layout/Flexbox\">Flexbox</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/CSS_layout/Grids\">CSS grid layout</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/CSS_layout/Responsive_Design\">Responsive design</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/CSS_layout/Media_queries\">Media query fundamentals</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/CSS_layout/Fundamental_Layout_Comprehension\">Challenge: Fundamental layout comprehension</a></li></ol></details></li><li class=\"toggle\"><details open=\"\"><summary><a href=\"/en-US/docs/Learn_web_development/Core/Scripting\">Dynamic scripting with JavaScript</a></summary><ol><li><a href=\"/en-US/docs/Learn_web_development/Core/Scripting/What_is_JavaScript\">What is JavaScript?</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Scripting/A_first_splash\">A first splash into JavaScript</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Scripting/What_went_wrong\">What went wrong? Troubleshooting JavaScript</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Scripting/Variables\">Storing the information you need — Variables</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Scripting/Math\">Basic math in JavaScript — numbers and operators</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Scripting/Strings\">Handling text — strings in JavaScript</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Scripting/Useful_string_methods\">Useful string methods</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Scripting/Arrays\">Arrays</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Scripting/Silly_story_generator\">Challenge: Silly story generator</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Scripting/Conditionals\">Making decisions in your code — conditionals</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Scripting/Loops\">Looping code</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Scripting/Functions\">Functions — reusable blocks of code</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Scripting/Build_your_own_function\">Build your own function</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Scripting/Return_values\">Function return values</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Scripting/Events\">Introduction to events</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Scripting/Event_bubbling\">Event bubbling</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Scripting/Image_gallery\">Challenge: Image gallery</a></li><li><em><a href=\"/en-US/docs/Learn_web_development/Core/Scripting/Object_basics\" aria-current=\"page\">JavaScript object basics</a></em></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Scripting/DOM_scripting\">DOM scripting introduction</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Scripting/Network_requests\">Making network requests with JavaScript</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Scripting/JSON\">Working with JSON</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Scripting/Debugging_JavaScript\">Debugging JavaScript and handling errors</a></li></ol></details></li><li class=\"toggle\"><details><summary><a href=\"/en-US/docs/Learn_web_development/Core/Frameworks_libraries\">JavaScript frameworks and libraries</a></summary><ol><li><a href=\"/en-US/docs/Learn_web_development/Core/Frameworks_libraries/Introduction\">Introduction to client-side frameworks</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Frameworks_libraries/Main_features\">Framework main features</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Frameworks_libraries/React_getting_started\">Getting started with React</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Frameworks_libraries/React_todo_list_beginning\">Beginning our React todo list</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Frameworks_libraries/React_components\">Componentizing our React app</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Frameworks_libraries/React_interactivity_events_state\">React interactivity: Events and state</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Frameworks_libraries/React_interactivity_filtering_conditional_rendering\">React interactivity: Editing, filtering, conditional rendering</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Frameworks_libraries/React_accessibility\">Accessibility in React</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Frameworks_libraries/React_resources\">React resources</a></li></ol></details></li><li class=\"toggle\"><details><summary><a href=\"/en-US/docs/Learn_web_development/Core/Accessibility\">Accessibility</a></summary><ol><li><a href=\"/en-US/docs/Learn_web_development/Core/Accessibility/What_is_accessibility\">What is accessibility?</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Accessibility/Tooling\">Accessibility tooling and assistive technology</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Accessibility/HTML\">HTML: A good basis for accessibility</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Accessibility/CSS_and_JavaScript\">CSS and JavaScript accessibility best practices</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Accessibility/WAI-ARIA_basics\">WAI-ARIA basics</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Accessibility/Multimedia\">Accessible multimedia</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Accessibility/Mobile\">Mobile accessibility</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Accessibility/Accessibility_troubleshooting\">Challenge: Accessibility troubleshooting</a></li></ol></details></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Design_for_developers\">Design for developers</a></li><li><a href=\"/en-US/docs/Learn_web_development/Core/Version_control\">Version control</a></li><li class=\"section\"><a href=\"/en-US/docs/Learn_web_development/Extensions\">Extension modules</a></li><li class=\"toggle\"><details><summary><a href=\"/en-US/docs/Learn_web_development/Extensions/Advanced_JavaScript_objects\">Advanced JavaScript objects</a></summary><ol><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Advanced_JavaScript_objects/Object_prototypes\">Object prototypes</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Advanced_JavaScript_objects/Object-oriented_programming\">Object-oriented programming</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Advanced_JavaScript_objects/Classes_in_JavaScript\">Classes in JavaScript</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Advanced_JavaScript_objects/Object_building_practice\">Object building practice</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Advanced_JavaScript_objects/Adding_bouncing_balls_features\">Challenge: Adding features to our bouncing balls demo</a></li></ol></details></li><li class=\"toggle\"><details><summary><a href=\"/en-US/docs/Learn_web_development/Extensions/Client-side_APIs\">Client-side web APIs</a></summary><ol><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Client-side_APIs/Introduction\">Introduction to web APIs</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Client-side_APIs/Video_and_audio_APIs\">Video and Audio APIs</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Client-side_APIs/Drawing_graphics\">Drawing graphics</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Client-side_APIs/Client-side_storage\">Client-side storage</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Client-side_APIs/Third_party_APIs\">Third-party APIs</a></li></ol></details></li><li class=\"toggle\"><details><summary><a href=\"/en-US/docs/Learn_web_development/Extensions/Async_JS\">Asynchronous JavaScript</a></summary><ol><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Async_JS/Introducing\">Introducing asynchronous JavaScript</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Async_JS/Promises\">How to use promises</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Async_JS/Implementing_a_promise-based_API\">How to implement a promise-based API</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Async_JS/Introducing_workers\">Introducing workers</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Async_JS/Sequencing_animations\">Challenge: Sequencing animations</a></li></ol></details></li><li class=\"toggle\"><details><summary><a href=\"/en-US/docs/Learn_web_development/Extensions/Forms\">Web forms</a></summary><ol><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Forms/Your_first_form\">Your first form</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Forms/How_to_structure_a_web_form\">How to structure a web form</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Forms/Basic_native_form_controls\">Basic native form controls</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Forms/HTML5_input_types\">The HTML5 input types</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Forms/Other_form_controls\">Other form controls</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Forms/Styling_web_forms\">Styling web forms</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Forms/Advanced_form_styling\">Advanced form styling</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Forms/UI_pseudo-classes\">UI pseudo-classes</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Forms/Form_validation\">Client-side form validation</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Forms/Sending_and_retrieving_form_data\">Sending form data</a></li></ol></details></li><li class=\"toggle\"><details><summary><a href=\"/en-US/docs/Learn_web_development/Extensions/Client-side_tools\">Understanding client-side tools</a></summary><ol><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Client-side_tools/Overview\">Client-side tooling overview</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Client-side_tools/Package_management\">Package management basics</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Client-side_tools/Introducing_complete_toolchain\">Introducing a complete toolchain</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Client-side_tools/Deployment\">Deploying our app</a></li></ol></details></li><li class=\"toggle\"><details><summary><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side\">Server-side websites</a></summary><ol><li class=\"toggle\"><details><summary><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side/First_steps\">Server-side first steps</a></summary><ol><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side/First_steps/Introduction\">Introduction to the server side</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side/First_steps/Client-Server_overview\">Client-Server Overview</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side/First_steps/Web_frameworks\">Server-side web frameworks</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side/First_steps/Website_security\">Website security</a></li></ol></details></li><li class=\"toggle\"><details><summary><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side/Django\">Django web framework (Python)</a></summary><ol><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side/Django/Introduction\">Django introduction</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side/Django/development_environment\">Setting up a Django development environment</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side/Django/Tutorial_local_library_website\">Django Tutorial: The Local Library website</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side/Django/skeleton_website\">Django Tutorial Part 2: Creating a skeleton website</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side/Django/Models\">Django Tutorial Part 3: Using models</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side/Django/Admin_site\">Django Tutorial Part 4: Django admin site</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side/Django/Home_page\">Django Tutorial Part 5: Creating our home page</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side/Django/Generic_views\">Django Tutorial Part 6: Generic list and detail views</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side/Django/Sessions\">Django Tutorial Part 7: Sessions framework</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side/Django/Authentication\">Django Tutorial Part 8: User authentication and permissions</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side/Django/Forms\">Django Tutorial Part 9: Working with forms</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side/Django/Testing\">Django Tutorial Part 10: Testing a Django web application</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side/Django/Deployment\">Django Tutorial Part 11: Deploying Django to production</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side/Django/web_application_security\">Django web application security</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side/Django/django_assessment_blog\">Assessment: DIY Django mini blog</a></li></ol></details></li><li class=\"toggle\"><details><summary><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side/Express_Nodejs\">Express web framework (Node.js)</a></summary><ol><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side/Express_Nodejs/Introduction\">Express/Node introduction</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side/Express_Nodejs/development_environment\">Setting up a Node development environment</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side/Express_Nodejs/Tutorial_local_library_website\">Express Tutorial: The Local Library website</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side/Express_Nodejs/skeleton_website\">Express Tutorial Part 2: Creating a skeleton website</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side/Express_Nodejs/mongoose\">Express Tutorial Part 3: Using a Database (with Mongoose)</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side/Express_Nodejs/routes\">Express Tutorial Part 4: Routes and controllers</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side/Express_Nodejs/Displaying_data\">Express Tutorial Part 5: Displaying library data</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side/Express_Nodejs/forms\">Express Tutorial Part 6: Working with forms</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Server-side/Express_Nodejs/deployment\">Express Tutorial Part 7: Deploying to production</a></li></ol></details></li></ol></details></li><li class=\"toggle\"><details><summary><a href=\"/en-US/docs/Learn_web_development/Extensions/Performance\">Web performance</a></summary><ol><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Performance/why_web_performance\">The \"why\" of web performance</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Performance/What_is_web_performance\">What is web performance?</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Performance/Perceived_performance\">Perceived performance</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Performance/Measuring_performance\">Measuring performance</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Performance/Multimedia\">Multimedia: Images</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Performance/video\">Multimedia: video</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Performance/JavaScript\">JavaScript performance optimization</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Performance/HTML\">HTML performance optimization</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Performance/CSS\">CSS performance optimization</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Performance/business_case_for_performance\">The business case for web performance</a></li></ol></details></li><li class=\"toggle\"><details><summary><a href=\"/en-US/docs/Learn_web_development/Extensions/Testing\">Testing</a></summary><ol><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Testing/Introduction\">Introduction to cross-browser testing</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Testing/Testing_strategies\">Strategies for carrying out testing</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Testing/HTML_and_CSS\">Handling common HTML and CSS problems</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Testing/Feature_detection\">Implementing feature detection</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Testing/Automated_testing\">Introduction to automated testing</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Testing/Your_own_automation_environment\">Setting up your own test automation environment</a></li></ol></details></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Transform_animate\">Transform and animate CSS</a></li><li><a href=\"/en-US/docs/Learn_web_development/Extensions/Security_privacy\">Security and privacy</a></li><li class=\"section\">Further resources</li><li class=\"toggle\"><details><summary><a href=\"/en-US/docs/Learn_web_development/Howto\">How to solve common problems</a></summary><ol><li><a href=\"/en-US/docs/Learn_web_development/Howto/Solve_HTML_problems\">Solve common HTML problems</a></li><li><a href=\"/en-US/docs/Learn_web_development/Howto/Solve_CSS_problems\">Solve common CSS problems</a></li><li><a href=\"/en-US/docs/Learn_web_development/Howto/Solve_JavaScript_problems\">Solve common JavaScript problems</a></li><li><a href=\"/en-US/docs/Learn_web_development/Howto/Web_mechanics\">Web mechanics</a></li><li><a href=\"/en-US/docs/Learn_web_development/Howto/Tools_and_setup\">Tools and setup</a></li><li><a href=\"/en-US/docs/Learn_web_development/Howto/Design_and_accessibility\">Design and accessibility</a></li></ol></details></li><li><a href=\"/en-US/docs/Learn_web_development/About\">About</a></li><li><a href=\"/en-US/docs/Learn_web_development/Educators\">Resources for educators</a></li><li><a href=\"/en-US/docs/Learn_web_development/Changelog\">Changelog</a></li></ol>","source":{"folder":"en-us/learn_web_development/core/scripting/object_basics","github_url":"https://github.com/mdn/content/blob/main/files/en-us/learn_web_development/core/scripting/object_basics/index.md","last_commit_url":"https://github.com/mdn/content/commit/5b20f5f4265f988f80f513db0e4b35c7e0cd70dc","filename":"index.md"},"summary":"In this article, we'll look at fundamental JavaScript object syntax, and revisit some JavaScript features that we've already seen earlier in the course, reiterating the fact that many of the features you've already dealt with are objects.","title":"JavaScript object basics","toc":[{"text":"Object basics","id":"object_basics"},{"text":"Dot notation","id":"dot_notation"},{"text":"Bracket notation","id":"bracket_notation"},{"text":"Setting object members","id":"setting_object_members"},{"text":"What is \"this\"?","id":"what_is_this"},{"text":"Introducing constructors","id":"introducing_constructors"},{"text":"You've been using objects all along","id":"youve_been_using_objects_all_along"},{"text":"Test your skills!","id":"test_your_skills!"},{"text":"Summary","id":"summary"}],"pageType":"learn-module-chapter"}}</script></body></html>