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>HTML attribute: pattern - HTML: HyperText Markup Language | MDN</title><link rel="alternate" title="HTML-Attribut: pattern" href="https://developer.mozilla.org/de/docs/Web/HTML/Attributes/pattern" hrefLang="de"/><link rel="alternate" title="Attribut HTML : pattern" href="https://developer.mozilla.org/fr/docs/Web/HTML/Attributes/pattern" hrefLang="fr"/><link rel="alternate" title="HTML 属性: pattern" href="https://developer.mozilla.org/ja/docs/Web/HTML/Attributes/pattern" hrefLang="ja"/><link rel="alternate" title="HTML attribute: pattern" href="https://developer.mozilla.org/ru/docs/Web/HTML/Attributes/pattern" hrefLang="ru"/><link rel="alternate" title="HTML 属性：pattern" href="https://developer.mozilla.org/zh-CN/docs/Web/HTML/Attributes/pattern" hrefLang="zh"/><link rel="alternate" title="HTML attribute: pattern" href="https://developer.mozilla.org/en-US/docs/Web/HTML/Attributes/pattern" 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="The pattern attribute specifies a regular expression the form control's value should match. If a non-null value doesn't conform to the constraints set by the pattern value, the ValidityState object's read-only patternMismatch property will be true."/><meta property="og:url" content="https://developer.mozilla.org/en-US/docs/Web/HTML/Attributes/pattern"/><meta property="og:title" content="HTML attribute: pattern - HTML: HyperText Markup Language | MDN"/><meta property="og:type" content="website"/><meta property="og:locale" content="en_US"/><meta property="og:description" content="The pattern attribute specifies a regular expression the form control's value should match. If a non-null value doesn't conform to the constraints set by the pattern value, the ValidityState object's read-only patternMismatch property will be true."/><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/Web/HTML/Attributes/pattern"/><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.5e889624.js"></script><link href="/static/css/main.26c64ea7.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-html 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 active"><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="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 "><button type="button" id="guides-button" class="top-level-entry menu-toggle" aria-controls="guides-menu" aria-expanded="false">Guides</button><a href="/en-US/docs/Learn" class="top-level-entry">Guides</a><ul id="guides-menu" class="submenu guides hidden inline-submenu-lg" aria-labelledby="guides-button"><li class="apis-link-container mobile-only "><a href="/en-US/docs/Learn" 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" 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/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">Learn to structure web content with HTML</p></div></a></li><li class="css-link-container "><a href="/en-US/docs/Learn/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">Learn to style content using CSS</p></div></a></li><li class="javascript-link-container "><a href="/en-US/docs/Learn/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">Learn to run scripts in the browser</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">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%2FWeb%2FHTML%2FAttributes%2Fpattern" class="login-link" rel="nofollow">Log in</a></li><li><a href="/users/fxa/login/authenticate/?next=%2Fen-US%2Fdocs%2FWeb%2FHTML%2FAttributes%2Fpattern" 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/Web" class="breadcrumb" property="item" typeof="WebPage"><span property="name">References</span></a><meta property="position" content="1"/></li><li property="itemListElement" typeof="ListItem"><a href="/en-US/docs/Web/HTML" class="breadcrumb" property="item" typeof="WebPage"><span property="name">HTML</span></a><meta property="position" content="2"/></li><li property="itemListElement" typeof="ListItem"><a href="/en-US/docs/Web/HTML/Attributes" class="breadcrumb" property="item" typeof="WebPage"><span property="name">Attributes</span></a><meta property="position" content="3"/></li><li property="itemListElement" typeof="ListItem"><a href="/en-US/docs/Web/HTML/Attributes/pattern" class="breadcrumb-current-page" property="item" typeof="WebPage"><span property="name">pattern</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/Web/HTML/Attributes/pattern" 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="fr" href="/fr/docs/Web/HTML/Attributes/pattern" class="button submenu-item"><span>Français</span></a></li><li class=" "><a data-locale="ja" href="/ja/docs/Web/HTML/Attributes/pattern" class="button submenu-item"><span>日本語</span></a></li><li class=" "><a data-locale="ru" href="/ru/docs/Web/HTML/Attributes/pattern" class="button submenu-item"><span>Русский</span></a></li><li class=" "><a data-locale="zh-CN" href="/zh-CN/docs/Web/HTML/Attributes/pattern" class="button submenu-item"><span>中文 (简体)</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" data-macro="HTMLSidebar"><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="#try_it">Try it</a></li><li class="document-toc-item "><a class="document-toc-link" href="#overview">Overview</a></li><li class="document-toc-item "><a class="document-toc-link" href="#examples">Examples</a></li><li class="document-toc-item "><a class="document-toc-link" href="#specifications">Specifications</a></li><li class="document-toc-item "><a class="document-toc-link" href="#browser_compatibility">Browser compatibility</a></li><li class="document-toc-item "><a class="document-toc-link" href="#see_also">See also</a></li></ul></section></div></div><div class="sidebar-body"> <ol> <li class="section"><a href="/en-US/docs/Web/HTML">HTML</a></li> <li class="section"><a href="/en-US/docs/Learn/HTML">Tutorials</a></li> <li><a href="/en-US/docs/Learn/Getting_started_with_the_web/HTML_basics">HTML basics</a></li> <li class="toggle"> <details> <summary>Introduction to HTML</summary> <ol> <li><a href="/en-US/docs/Learn/HTML/Introduction_to_HTML">Introduction to HTML overview</a></li> <li><a href="/en-US/docs/Learn/HTML/Introduction_to_HTML/Getting_started">Getting started with HTML</a></li> <li><a href="/en-US/docs/Learn/HTML/Introduction_to_HTML/The_head_metadata_in_HTML">What's in the head? Metadata in HTML</a></li> <li><a href="/en-US/docs/Learn/HTML/Introduction_to_HTML/HTML_text_fundamentals">HTML text fundamentals</a></li> <li><a href="/en-US/docs/Learn/HTML/Introduction_to_HTML/Creating_hyperlinks">Creating hyperlinks</a></li> <li><a href="/en-US/docs/Learn/HTML/Introduction_to_HTML/Advanced_text_formatting">Advanced text formatting</a></li> <li><a href="/en-US/docs/Learn/HTML/Introduction_to_HTML/Document_and_website_structure">Document and website structure</a></li> <li><a href="/en-US/docs/Learn/HTML/Introduction_to_HTML/Debugging_HTML">Debugging HTML</a></li> <li><a href="/en-US/docs/Learn/HTML/Introduction_to_HTML/Marking_up_a_letter">Assessment: Marking up a letter</a></li> <li><a href="/en-US/docs/Learn/HTML/Introduction_to_HTML/Structuring_a_page_of_content">Assessment: Structuring a page of content</a></li> </ol> </details> </li> <li class="toggle"> <details> <summary>Multimedia and embedding</summary> <ol> <li><a href="/en-US/docs/Learn/HTML/Multimedia_and_embedding">Multimedia and embedding overview</a></li> <li><a href="/en-US/docs/Learn/HTML/Multimedia_and_embedding/Images_in_HTML">Images in HTML</a></li> <li><a href="/en-US/docs/Learn/HTML/Multimedia_and_embedding/Video_and_audio_content">Video and audio content</a></li> <li><a href="/en-US/docs/Learn/HTML/Multimedia_and_embedding/Other_embedding_technologies">From object to iframe — other embedding technologies</a></li> <li><a href="/en-US/docs/Learn/HTML/Multimedia_and_embedding/Adding_vector_graphics_to_the_Web">Adding vector graphics to the web</a></li> <li><a href="/en-US/docs/Learn/HTML/Multimedia_and_embedding/Responsive_images">Responsive images</a></li> <li><a href="/en-US/docs/Learn/HTML/Multimedia_and_embedding/Mozilla_splash_page">Assessment: Mozilla splash page</a></li> </ol> </details> </li> <li class="toggle"> <details> <summary>HTML tables</summary> <ol> <li><a href="/en-US/docs/Learn/HTML/Tables">HTML tables overview</a></li> <li><a href="/en-US/docs/Learn/HTML/Tables/Basics">HTML table basics</a></li> <li><a href="/en-US/docs/Learn/HTML/Tables/Advanced">HTML table advanced features and accessibility</a></li> <li><a href="/en-US/docs/Learn/HTML/Tables/Structuring_planet_data">Assessment: Structuring planet data</a></li> </ol> </details> </li> <li class="section"><a href="/en-US/docs/Web/HTML/Reference">References</a></li> <li class="toggle"> <details> <summary>HTML elements</summary> <ol><li><a href="/en-US/docs/Web/HTML/Element/a"><code><a></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/abbr"><code><abbr></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/acronym"><code><acronym></code></a><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTML/Element/address"><code><address></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/area"><code><area></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/article"><code><article></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/aside"><code><aside></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/audio"><code><audio></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/b"><code><b></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/base"><code><base></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/bdi"><code><bdi></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/bdo"><code><bdo></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/big"><code><big></code></a><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTML/Element/blockquote"><code><blockquote></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/body"><code><body></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/br"><code><br></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/button"><code><button></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/canvas"><code><canvas></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/caption"><code><caption></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/center"><code><center></code></a><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTML/Element/cite"><code><cite></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/code"><code><code></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/col"><code><col></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/colgroup"><code><colgroup></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/data"><code><data></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/datalist"><code><datalist></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/dd"><code><dd></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/del"><code><del></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/details"><code><details></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/dfn"><code><dfn></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/dialog"><code><dialog></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/dir"><code><dir></code></a><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTML/Element/div"><code><div></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/dl"><code><dl></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/dt"><code><dt></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/em"><code><em></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/embed"><code><embed></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/fencedframe"><code><fencedframe></code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTML/Element/fieldset"><code><fieldset></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/figcaption"><code><figcaption></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/figure"><code><figure></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/font"><code><font></code></a><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTML/Element/footer"><code><footer></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/form"><code><form></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/frame"><code><frame></code></a><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTML/Element/frameset"><code><frameset></code></a><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTML/Element/Heading_Elements"><code><h1></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/head"><code><head></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/header"><code><header></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/hgroup"><code><hgroup></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/hr"><code><hr></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/html"><code><html></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/i"><code><i></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/iframe"><code><iframe></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/img"><code><img></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/input"><code><input></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/ins"><code><ins></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/kbd"><code><kbd></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/label"><code><label></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/legend"><code><legend></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/li"><code><li></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/link"><code><link></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/main"><code><main></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/map"><code><map></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/mark"><code><mark></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/marquee"><code><marquee></code></a><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTML/Element/menu"><code><menu></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/meta"><code><meta></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/meter"><code><meter></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/nav"><code><nav></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/nobr"><code><nobr></code></a><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTML/Element/noembed"><code><noembed></code></a><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTML/Element/noframes"><code><noframes></code></a><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTML/Element/noscript"><code><noscript></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/object"><code><object></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/ol"><code><ol></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/optgroup"><code><optgroup></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/option"><code><option></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/output"><code><output></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/p"><code><p></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/param"><code><param></code></a><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTML/Element/picture"><code><picture></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/plaintext"><code><plaintext></code></a><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTML/Element/portal"><code><portal></code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTML/Element/pre"><code><pre></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/progress"><code><progress></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/q"><code><q></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/rb"><code><rb></code></a><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTML/Element/rp"><code><rp></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/rt"><code><rt></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/rtc"><code><rtc></code></a><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTML/Element/ruby"><code><ruby></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/s"><code><s></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/samp"><code><samp></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/script"><code><script></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/search"><code><search></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/section"><code><section></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/select"><code><select></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/slot"><code><slot></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/small"><code><small></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/source"><code><source></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/span"><code><span></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/strike"><code><strike></code></a><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTML/Element/strong"><code><strong></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/style"><code><style></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/sub"><code><sub></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/summary"><code><summary></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/sup"><code><sup></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/table"><code><table></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/tbody"><code><tbody></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/td"><code><td></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/template"><code><template></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/textarea"><code><textarea></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/tfoot"><code><tfoot></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/th"><code><th></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/thead"><code><thead></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/time"><code><time></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/title"><code><title></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/tr"><code><tr></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/track"><code><track></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/tt"><code><tt></code></a><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li><li><a href="/en-US/docs/Web/HTML/Element/u"><code><u></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/ul"><code><ul></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/var"><code><var></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/video"><code><video></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/wbr"><code><wbr></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/xmp"><code><xmp></code></a><abbr class="icon icon-deprecated" title="Deprecated. Not for use in new websites."> <span class="visually-hidden">Deprecated</span> </abbr></li></ol> </details> </li> <li class="toggle"> <details> <summary>Global attributes</summary> <ol><li><a href="/en-US/docs/Web/HTML/Global_attributes/accesskey"><code>accesskey</code></a></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/anchor"><code>anchor</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr><abbr class="icon icon-nonstandard" title="Non-standard. Check cross-browser support before using."> <span class="visually-hidden">Non-standard</span> </abbr></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/autocapitalize"><code>autocapitalize</code></a></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/autocorrect"><code>autocorrect</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/autofocus"><code>autofocus</code></a></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/class"><code>class</code></a></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/contenteditable"><code>contenteditable</code></a></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/data-*"><code>data-*</code></a></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/dir"><code>dir</code></a></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/draggable"><code>draggable</code></a></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/enterkeyhint"><code>enterkeyhint</code></a></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/exportparts"><code>exportparts</code></a></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/hidden"><code>hidden</code></a></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/id"><code>id</code></a></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/inert"><code>inert</code></a></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/inputmode"><code>inputmode</code></a></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/is"><code>is</code></a></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/itemid"><code>itemid</code></a></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/itemprop"><code>itemprop</code></a></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/itemref"><code>itemref</code></a></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/itemscope"><code>itemscope</code></a></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/itemtype"><code>itemtype</code></a></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/lang"><code>lang</code></a></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/nonce"><code>nonce</code></a></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/part"><code>part</code></a></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/popover"><code>popover</code></a></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/slot"><code>slot</code></a></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/spellcheck"><code>spellcheck</code></a></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/style"><code>style</code></a></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/tabindex"><code>tabindex</code></a></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/title"><code>title</code></a></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/translate"><code>translate</code></a></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/virtualkeyboardpolicy"><code>virtualkeyboardpolicy</code></a><abbr class="icon icon-experimental" title="Experimental. Expect behavior to change in the future."> <span class="visually-hidden">Experimental</span> </abbr></li><li><a href="/en-US/docs/Web/HTML/Global_attributes/writingsuggestions"><code>writingsuggestions</code></a></li></ol> </details> </li> <li class="toggle"> <details open=""> <summary>Attributes</summary> <ol> <li><a href="/en-US/docs/Web/HTML/Attributes/accept">accept</a></li> <li><a href="/en-US/docs/Web/HTML/Attributes/autocomplete">autocomplete</a></li> <li><a href="/en-US/docs/Web/HTML/Attributes/capture">capture</a></li> <li><a href="/en-US/docs/Web/HTML/Attributes/crossorigin">crossorigin</a></li> <li><a href="/en-US/docs/Web/HTML/Attributes/dirname">dirname</a></li> <li><a href="/en-US/docs/Web/HTML/Attributes/disabled">disabled</a></li> <li><a href="/en-US/docs/Web/HTML/Attributes/elementtiming">elementtiming</a></li> <li><a href="/en-US/docs/Web/HTML/Attributes/for">for</a></li> <li><a href="/en-US/docs/Web/HTML/Attributes/max">max</a></li> <li><a href="/en-US/docs/Web/HTML/Attributes/maxlength">maxlength</a></li> <li><a href="/en-US/docs/Web/HTML/Attributes/min">min</a></li> <li><a href="/en-US/docs/Web/HTML/Attributes/minlength">minlength</a></li> <li><a href="/en-US/docs/Web/HTML/Attributes/multiple">multiple</a></li> <li><em><a href="/en-US/docs/Web/HTML/Attributes/pattern" aria-current="page">pattern</a></em></li> <li><a href="/en-US/docs/Web/HTML/Attributes/placeholder">placeholder</a></li> <li><a href="/en-US/docs/Web/HTML/Attributes/readonly">readonly</a></li> <li><a href="/en-US/docs/Web/HTML/Attributes/rel">rel</a></li> <li><a href="/en-US/docs/Web/HTML/Attributes/required">required</a></li> <li><a href="/en-US/docs/Web/HTML/Attributes/size">size</a></li> <li><a href="/en-US/docs/Web/HTML/Attributes/step">step</a></li> </ol> </details> </li> <li class="toggle"> <details> <summary><code><input></code> types</summary> <ol><li><a href="/en-US/docs/Web/HTML/Element/input/button"><code><input type="button"></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/input/checkbox"><code><input type="checkbox"></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/input/color"><code><input type="color"></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/input/date"><code><input type="date"></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/input/datetime-local"><code><input type="datetime-local"></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/input/email"><code><input type="email"></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/input/file"><code><input type="file"></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/input/hidden"><code><input type="hidden"></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/input/image"><code><input type="image"></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/input/month"><code><input type="month"></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/input/number"><code><input type="number"></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/input/password"><code><input type="password"></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/input/radio"><code><input type="radio"></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/input/range"><code><input type="range"></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/input/reset"><code><input type="reset"></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/input/search"><code><input type="search"></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/input/submit"><code><input type="submit"></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/input/tel"><code><input type="tel"></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/input/text"><code><input type="text"></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/input/time"><code><input type="time"></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/input/url"><code><input type="url"></code></a></li><li><a href="/en-US/docs/Web/HTML/Element/input/week"><code><input type="week"></code></a></li></ol> </details> </li> <li class="section no-link">Guides</li> <li> <ol> <li><a href="/en-US/docs/Web/HTML/Content_categories">Content categories</a></li> <li><a href="/en-US/docs/Glossary/Block-level_content">Block-level elements</a></li> <li><a href="/en-US/docs/Glossary/Inline-level_content">Inline elements</a></li> <li><a href="/en-US/docs/Web/HTML/Quirks_Mode_and_Standards_Mode">Quirks Mode and Standards Mode</a></li> <li><a href="/en-US/docs/Web/HTML/Date_and_time_formats">Date and time formats used in HTML</a></li> <li><a href="/en-US/docs/Web/HTML/Constraint_validation">Constraint validation</a></li> <li><a href="/en-US/docs/Web/HTML/Microdata">Microdata</a></li> <li><a href="/en-US/docs/Web/HTML/microformats">Microformats</a></li> <li><a href="/en-US/docs/Web/HTML/Viewport_meta_tag">Viewport meta tag</a></li> <li><a href="/en-US/docs/Web/HTML/CORS_enabled_image">Allowing cross-origin use of images and canvas</a></li> </ol> </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="#try_it">Try it</a></li><li class="document-toc-item "><a class="document-toc-link" href="#overview">Overview</a></li><li class="document-toc-item "><a class="document-toc-link" href="#examples">Examples</a></li><li class="document-toc-item "><a class="document-toc-link" href="#specifications">Specifications</a></li><li class="document-toc-item "><a class="document-toc-link" href="#browser_compatibility">Browser compatibility</a></li><li class="document-toc-item "><a class="document-toc-link" href="#see_also">See also</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>HTML attribute: pattern</h1><details class="baseline-indicator high"><summary><span class="indicator" role="img" aria-label="Baseline Check"></span><h2>Baseline <span class="not-bold">Widely available</span></h2><div class="browsers"><span class="engine" title="Supported in Chrome and Edge"><span class="browser chrome supported" role="img" aria-label="Chrome check"></span><span class="browser edge supported" role="img" aria-label="Edge check"></span></span><span class="engine" title="Supported in Firefox"><span class="browser firefox supported" role="img" aria-label="Firefox check"></span></span><span class="engine" title="Supported in Safari"><span class="browser safari supported" role="img" aria-label="Safari check"></span></span></div><span class="icon icon-chevron "></span></summary><div class="extra"><p>This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.</p><ul><li><a href="/en-US/docs/Glossary/Baseline/Compatibility" data-glean="baseline_link_learn_more" target="_blank" class="learn-more">Learn more</a></li><li><a href="#browser_compatibility" data-glean="baseline_link_bcd_table">See full compatibility</a></li><li><a href="https://survey.alchemer.com/s3/7634825/MDN-baseline-feedback?page=%2Fen-US%2Fdocs%2FWeb%2FHTML%2FAttributes%2Fpattern&level=high" data-glean="baseline_link_feedback" class="feedback-link" target="_blank" rel="noreferrer">Report feedback</a></li></ul></div></details></header><div class="section-content"><p>The <strong><code>pattern</code></strong> attribute specifies a <a href="/en-US/docs/Web/JavaScript/Guide/Regular_expressions">regular expression</a> the form control's value should match. If a non-<code>null</code> value doesn't conform to the constraints set by the <code>pattern</code> value, the <a href="/en-US/docs/Web/API/ValidityState"><code>ValidityState</code></a> object's read-only <a href="/en-US/docs/Web/API/ValidityState/patternMismatch" title="patternMismatch"><code>patternMismatch</code></a> property will be true.</p></div><section aria-labelledby="try_it"><h2 id="try_it"><a href="#try_it">Try it</a></h2><div class="section-content"><iframe class="interactive is-tabbed-shorter-height" height="200" src="https://interactive-examples.mdn.mozilla.net/pages/tabbed/attribute-pattern.html" title="MDN Web Docs Interactive Example" allow="clipboard-write" loading="lazy"></iframe></div></section><section aria-labelledby="overview"><h2 id="overview"><a href="#overview">Overview</a></h2><div class="section-content"><p>The <code>pattern</code> attribute is an attribute of the <a href="/en-US/docs/Web/HTML/Element/input/text">text</a>, <a href="/en-US/docs/Web/HTML/Element/input/tel">tel</a>, <a href="/en-US/docs/Web/HTML/Element/input/email">email</a>, <a href="/en-US/docs/Web/HTML/Element/input/url">url</a>, <a href="/en-US/docs/Web/HTML/Element/input/password">password</a>, and <a href="/en-US/docs/Web/HTML/Element/input/search">search</a> input types.</p> <p>The <code>pattern</code> attribute, when specified, is a regular expression which the input's <a href="/en-US/docs/Web/HTML/Element/input#value"><code>value</code></a> must match for the value to pass <a href="/en-US/docs/Web/HTML/Constraint_validation">constraint validation</a>. It must be a valid JavaScript regular expression, as used by the <a href="/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp"><code>RegExp</code></a> type, and as documented in our <a href="/en-US/docs/Web/JavaScript/Guide/Regular_expressions">guide on regular expressions</a>.</p> <p>The pattern's regular expression is compiled with the <a href="/en-US/docs/Web/JavaScript/Reference/Regular_expressions/Character_class#v-mode_character_class"><code>'v'</code> flag</a>. This makes the regular expression <a href="/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/unicode#unicode-aware_mode">unicode-aware</a>, and also changes how character classes are interpreted. This allows character class set intersection and subtraction operations, and in addition to <code>]</code> and <code>\</code>, the following characters must be escaped using a <code>\</code> backslash if they represent literal characters: <code>(</code>, <code>)</code>, <code>[</code>, <code>{</code>, <code>}</code>, <code>/</code>, <code>-</code>, <code>|</code>. Before mid-2023, the <code>'u'</code> flag was specified instead; If you're updating older code, <a href="https://github.com/tc39/proposal-regexp-v-flag#how-is-the-v-flag-different-from-the-u-flag" class="external" target="_blank">this document outlines the differences</a>.</p> <p>The pattern's regular expression must match the entire input's <code>value</code>, rather than matching a substring - as if a <code>^(?:</code> were implied at the start of the pattern and <code>)$</code> at the end.</p> <p>No forward slashes should be specified around the pattern text. No regular expression is applied if the attribute value is absent, an empty string, or invalid.</p> <p>Some of the input types supporting the pattern attribute, notably the <a href="/en-US/docs/Web/HTML/Element/input/email">email</a> and <a href="/en-US/docs/Web/HTML/Element/input/url">url</a> input types, have expected value syntaxes that must be matched. If the pattern attribute isn't present, and the value doesn't match the expected syntax for that value type, the <a href="/en-US/docs/Web/API/ValidityState"><code>ValidityState</code></a> object's read-only <a href="/en-US/docs/Web/API/ValidityState/typeMismatch" title="typeMismatch"><code>typeMismatch</code></a> property will be true.</p></div></section><section aria-labelledby="constraint_validation"><h3 id="constraint_validation"><a href="#constraint_validation">Constraint validation</a></h3><div class="section-content"><p>If the input's value is not the empty string and the value does not match the entire regular expression, there is a constraint violation reported by the <a href="/en-US/docs/Web/API/ValidityState"><code>ValidityState</code></a> object's <a href="/en-US/docs/Web/API/ValidityState/patternMismatch" title="patternMismatch"><code>patternMismatch</code></a> property being <code>true</code>.</p> <div class="notecard note"> <p><strong>Note:</strong> If the <code>pattern</code> attribute is specified with no value, its value is implicitly the empty string. Thus, <strong>any non-empty</strong> input <code>value</code> will result in constraint violation.</p> </div></div></section><section aria-labelledby="usability_and_accessibility_considerations"><h3 id="usability_and_accessibility_considerations"><a href="#usability_and_accessibility_considerations">Usability and accessibility considerations</a></h3><div class="section-content"><p>When including a <code>pattern</code>, provide a description of the pattern in visible text near the control. Additionally, include a <a href="/en-US/docs/Web/HTML/Element/input#title"><code>title</code></a> attribute which gives a description of the pattern. User agents may use the title contents during constraint validation to tell the user that the pattern is not matched. Some browsers show a tooltip with title contents, improving usability for sighted users. Additionally, assistive technology may read the title aloud when the control gains focus, but this should not be relied upon for accessibility.</p> <p>Only relying on the <code>title</code> attribute for the visual display of text content is discouraged, as many user agents do not expose the attribute in an accessible manner. Although some browsers show a tooltip when an element with a title is hovered, that leaves out keyboard-only and touch-only users. This is one of the several reasons you must include information informing users how to fill out the control to match the requirements.</p> <p>While <code>title</code>s are used by some browsers to populate error messaging, because browsers sometimes also show the title as text on hover, it therefore shows in non-error situations, so be careful not to word titles as if an error has occurred.</p></div></section><section aria-labelledby="examples"><h2 id="examples"><a href="#examples">Examples</a></h2><div class="section-content"></div></section><section aria-labelledby="matching_a_phone_number"><h3 id="matching_a_phone_number"><a href="#matching_a_phone_number">Matching a phone number</a></h3><div class="section-content"><p>Given the following:</p> <div class="code-example"><div class="example-header"><span class="language-name">html</span></div><pre class="brush: html notranslate"><code><p> <label> Enter your phone number in the format (123) - 456 - 7890 (<input name="tel1" type="tel" pattern="[0-9]{3}" placeholder="###" aria-label="3-digit area code" size="2" />) - <input name="tel2" type="tel" pattern="[0-9]{3}" placeholder="###" aria-label="3-digit prefix" size="2" /> - <input name="tel3" type="tel" pattern="[0-9]{4}" placeholder="####" aria-label="4-digit number" size="3" /> </label> </p> </code></pre></div> <p>Here we have 3 sections for a north American phone number with an implicit label encompassing all three components of the phone number, expecting 3-digits, 3-digits and 4-digits respectively, as defined by the <code>pattern</code> attribute set on each.</p> <p>If the values are too long or too short, or contain characters that aren't digits, the <code>patternMismatch</code> will be true. When <code>true</code>, the element matches the <a href="/en-US/docs/Web/CSS/:invalid"><code>:invalid</code></a> CSS pseudo-classes.</p> <div class="code-example"><div class="example-header"><span class="language-name">css</span></div><pre class="brush: css notranslate"><code>input:invalid { border: red solid 3px; } </code></pre></div><div class="code-example"><div class="example-header"></div><iframe class="sample-code-frame" title="Matching a phone number sample" id="frame_matching_a_phone_number" width="300" height="80" src="about:blank" data-live-path="/en-US/docs/Web/HTML/Attributes/pattern" data-live-id="matching_a_phone_number" sandbox="allow-same-origin allow-scripts" loading="lazy"></iframe></div> <p>If we had used <a href="/en-US/docs/Web/HTML/Attributes/minlength"><code>minlength</code></a> and <a href="/en-US/docs/Web/HTML/Attributes/maxlength"><code>maxlength</code></a> attributes instead, we may have seen <a href="/en-US/docs/Web/API/ValidityState/tooLong"><code>validityState.tooLong</code></a> or <a href="/en-US/docs/Web/API/ValidityState/tooShort"><code>validityState.tooShort</code></a> being true.</p></div></section><section aria-labelledby="specifying_a_pattern"><h3 id="specifying_a_pattern"><a href="#specifying_a_pattern">Specifying a pattern</a></h3><div class="section-content"><p>You can use the <a href="/en-US/docs/Web/HTML/Element/input#pattern"><code>pattern</code></a> attribute to specify a regular expression that the inputted value must match in order to be considered valid (see <a href="/en-US/docs/Learn/Forms/Form_validation#validating_against_a_regular_expression">Validating against a regular expression</a> for a crash course on using regular expressions to validate inputs).</p> <p>The example below restricts the value to 4-8 characters and requires that it contain only lower-case letters.</p> <div class="code-example"><div class="example-header"><span class="language-name">html</span></div><pre class="brush: html notranslate"><code><form> <div> <label for="uname">Choose a username: </label> <input type="text" id="uname" name="name" required size="45" pattern="[a-z]{4,8}" title="4 to 8 lowercase letters" /> <span class="validity"></span> <p>Usernames must be lowercase and 4-8 characters in length.</p> </div> <div> <button>Submit</button> </div> </form> </code></pre></div> <div class="code-example"><pre class="brush: css hidden notranslate"><code>div { margin-bottom: 10px; position: relative; } p { font-size: 80%; color: #999; } input + span { padding-right: 30px; } input:invalid + span::after { position: absolute; content: "✖"; padding-left: 5px; } input:valid + span::after { position: absolute; content: "✓"; padding-left: 5px; } </code></pre></div> <p>This renders like so:</p><div class="code-example"><div class="example-header"></div><iframe class="sample-code-frame" title="Specifying a pattern sample" id="frame_specifying_a_pattern" width="600" height="110" src="about:blank" data-live-path="/en-US/docs/Web/HTML/Attributes/pattern" data-live-id="specifying_a_pattern" sandbox="allow-same-origin allow-scripts" loading="lazy"></iframe></div></div></section><h2 id="specifications"><a href="#specifications">Specifications</a></h2><table class="standard-table"><thead><tr><th scope="col">Specification</th></tr></thead><tbody><tr><td><a href="https://html.spec.whatwg.org/multipage/input.html#attr-input-pattern">HTML Standard <br/><small># attr-input-pattern</small></a></td></tr></tbody></table><h2 id="browser_compatibility"><a href="#browser_compatibility">Browser compatibility</a></h2><p>BCD tables only load in the browser<noscript> with JavaScript enabled. Enable JavaScript to view data.</noscript></p><section aria-labelledby="see_also"><h2 id="see_also"><a href="#see_also">See also</a></h2><div class="section-content"><ul> <li><a href="/en-US/docs/Web/HTML/Constraint_validation">Constraint validation</a></li> <li><a href="/en-US/docs/Learn/Forms/Form_validation">Forms: Data form validation</a></li> <li><a href="/en-US/docs/Web/JavaScript/Guide/Regular_expressions">Regular Expressions</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="2024-11-21T09:46:52.000Z">Nov 21, 2024</time> by <a href="/en-US/docs/Web/HTML/Attributes/pattern/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/web/html/attributes/pattern/index.md?plain=1" title="Folder: en-us/web/html/attributes/pattern (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%2FWeb%2FHTML%2FAttributes%2Fpattern&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%2Fweb%2Fhtml%2Fattributes%2Fpattern%60%0A*+MDN+URL%3A+https%3A%2F%2Fdeveloper.mozilla.org%2Fen-US%2Fdocs%2FWeb%2FHTML%2FAttributes%2Fpattern%0A*+GitHub+URL%3A+https%3A%2F%2Fgithub.com%2Fmdn%2Fcontent%2Fblob%2Fmain%2Ffiles%2Fen-us%2Fweb%2Fhtml%2Fattributes%2Fpattern%2Findex.md%0A*+Last+commit%3A+https%3A%2F%2Fgithub.com%2Fmdn%2Fcontent%2Fcommit%2F4d3605197ea5c6407aacca2a80cc27a398f04fc8%0A*+Document+last+modified%3A+2024-11-21T09%3A46%3A52.000Z%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://mozilla.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 width="112" height="32" fill="none" xmlns="http://www.w3.org/2000/svg"><title id="mozilla-footer-logo-svg">Mozilla logo</title><path d="M41.753 14.218c-2.048 0-3.324 1.522-3.324 4.157 0 2.423 1.119 4.286 3.29 4.286 2.082 0 3.447-1.678 3.447-4.347 0-2.826-1.522-4.096-3.413-4.096Zm54.89 7.044c0 .901.437 1.618 1.645 1.618 1.427 0 2.949-1.024 3.044-3.352-.649-.095-1.365-.185-2.02-.185-1.426-.005-2.668.397-2.668 1.92Z" fill="currentColor"></path><path d="M0 0v32h111.908V0H0Zm32.56 25.426h-5.87v-7.884c0-2.423-.806-3.352-2.39-3.352-1.924 0-2.702 1.365-2.702 3.324v4.868h1.864v3.044h-5.864v-7.884c0-2.423-.806-3.352-2.39-3.352-1.924 0-2.702 1.365-2.702 3.324v4.868h2.669v3.044H6.642v-3.044h1.863v-7.918H6.642V11.42h5.864v2.11c.839-1.489 2.3-2.39 4.252-2.39 2.02 0 3.878.963 4.566 3.01.778-1.862 2.361-3.01 4.566-3.01 2.512 0 4.812 1.522 4.812 4.84v6.402h1.863v3.044h-.005Zm9.036.307c-4.314 0-7.296-2.635-7.296-7.106 0-4.096 2.484-7.481 7.514-7.481s7.481 3.38 7.481 7.29c0 4.472-3.228 7.297-7.699 7.297Zm22.578-.307H51.942l-.403-2.11 7.7-8.846h-4.376l-.621 2.17-2.888-.313.498-4.907h12.294l.313 2.11-7.767 8.852h4.533l.654-2.172 3.167.308-.872 4.908Zm7.99 0h-4.191v-5.03h4.19v5.03Zm0-8.976h-4.191v-5.03h4.19v5.03Zm2.618 8.976 6.054-21.358h3.945l-6.054 21.358h-3.945Zm8.136 0 6.048-21.358h3.945l-6.054 21.358h-3.939Zm21.486.307c-1.863 0-2.887-1.085-3.072-2.792-.805 1.427-2.232 2.792-4.498 2.792-2.02 0-4.314-1.085-4.314-4.006 0-3.447 3.323-4.253 6.518-4.253.778 0 1.584.034 2.3.124v-.465c0-1.427-.034-3.133-2.3-3.133-.84 0-1.488.061-2.143.402l-.453 1.578-3.195-.34.549-3.224c2.45-.996 3.692-1.27 5.992-1.27 3.01 0 5.556 1.55 5.556 4.75v6.083c0 .805.314 1.085.963 1.085.184 0 .375-.034.587-.095l.034 2.11a5.432 5.432 0 0 1-2.524.654Z" fill="currentColor"></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 ©1998–2024 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/Web/HTML/Attributes/pattern","doc":{"isMarkdown":true,"isTranslated":false,"isActive":true,"flaws":{},"title":"HTML attribute: pattern","mdn_url":"/en-US/docs/Web/HTML/Attributes/pattern","locale":"en-US","native":"English (US)","browserCompat":["html.elements.input.pattern"],"baseline":{"baseline":"high","baseline_high_date":"2018-01-29","baseline_low_date":"2015-07-29","support":{"chrome":"1","chrome_android":"18","edge":"12","firefox":"1","firefox_android":"4","safari":"1","safari_ios":"1"}},"sidebarHTML":"\n <ol>\n <li class=\"section\"><a href=\"/en-US/docs/Web/HTML\">HTML</a></li>\n <li class=\"section\"><a href=\"/en-US/docs/Learn/HTML\">Tutorials</a></li>\n <li><a href=\"/en-US/docs/Learn/Getting_started_with_the_web/HTML_basics\">HTML basics</a></li>\n <li class=\"toggle\">\n <details>\n <summary>Introduction to HTML</summary>\n <ol>\n <li><a href=\"/en-US/docs/Learn/HTML/Introduction_to_HTML\">Introduction to HTML overview</a></li>\n <li><a href=\"/en-US/docs/Learn/HTML/Introduction_to_HTML/Getting_started\">Getting started with HTML</a></li>\n <li><a href=\"/en-US/docs/Learn/HTML/Introduction_to_HTML/The_head_metadata_in_HTML\">What's in the head? Metadata in HTML</a></li>\n <li><a href=\"/en-US/docs/Learn/HTML/Introduction_to_HTML/HTML_text_fundamentals\">HTML text fundamentals</a></li>\n <li><a href=\"/en-US/docs/Learn/HTML/Introduction_to_HTML/Creating_hyperlinks\">Creating hyperlinks</a></li>\n <li><a href=\"/en-US/docs/Learn/HTML/Introduction_to_HTML/Advanced_text_formatting\">Advanced text formatting</a></li>\n <li><a href=\"/en-US/docs/Learn/HTML/Introduction_to_HTML/Document_and_website_structure\">Document and website structure</a></li>\n <li><a href=\"/en-US/docs/Learn/HTML/Introduction_to_HTML/Debugging_HTML\">Debugging HTML</a></li>\n <li><a href=\"/en-US/docs/Learn/HTML/Introduction_to_HTML/Marking_up_a_letter\">Assessment: Marking up a letter</a></li>\n <li><a href=\"/en-US/docs/Learn/HTML/Introduction_to_HTML/Structuring_a_page_of_content\">Assessment: Structuring a page of content</a></li>\n </ol>\n </details>\n </li>\n <li class=\"toggle\">\n <details>\n <summary>Multimedia and embedding</summary>\n <ol>\n <li><a href=\"/en-US/docs/Learn/HTML/Multimedia_and_embedding\">Multimedia and embedding overview</a></li>\n <li><a href=\"/en-US/docs/Learn/HTML/Multimedia_and_embedding/Images_in_HTML\">Images in HTML</a></li>\n <li><a href=\"/en-US/docs/Learn/HTML/Multimedia_and_embedding/Video_and_audio_content\">Video and audio content</a></li>\n <li><a href=\"/en-US/docs/Learn/HTML/Multimedia_and_embedding/Other_embedding_technologies\">From object to iframe — other embedding technologies</a></li>\n <li><a href=\"/en-US/docs/Learn/HTML/Multimedia_and_embedding/Adding_vector_graphics_to_the_Web\">Adding vector graphics to the web</a></li>\n <li><a href=\"/en-US/docs/Learn/HTML/Multimedia_and_embedding/Responsive_images\">Responsive images</a></li>\n <li><a href=\"/en-US/docs/Learn/HTML/Multimedia_and_embedding/Mozilla_splash_page\">Assessment: Mozilla splash page</a></li>\n </ol>\n </details>\n </li>\n <li class=\"toggle\">\n <details>\n <summary>HTML tables</summary>\n <ol>\n <li><a href=\"/en-US/docs/Learn/HTML/Tables\">HTML tables overview</a></li>\n <li><a href=\"/en-US/docs/Learn/HTML/Tables/Basics\">HTML table basics</a></li>\n <li><a href=\"/en-US/docs/Learn/HTML/Tables/Advanced\">HTML table advanced features and accessibility</a></li>\n <li><a href=\"/en-US/docs/Learn/HTML/Tables/Structuring_planet_data\">Assessment: Structuring planet data</a></li>\n </ol>\n </details>\n </li>\n <li class=\"section\"><a href=\"/en-US/docs/Web/HTML/Reference\">References</a></li>\n <li class=\"toggle\">\n <details>\n <summary>HTML elements</summary>\n <ol><li><a href=\"/en-US/docs/Web/HTML/Element/a\"><code><a></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/abbr\"><code><abbr></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/acronym\"><code><acronym></code></a><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTML/Element/address\"><code><address></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/area\"><code><area></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/article\"><code><article></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/aside\"><code><aside></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/audio\"><code><audio></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/b\"><code><b></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/base\"><code><base></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/bdi\"><code><bdi></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/bdo\"><code><bdo></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/big\"><code><big></code></a><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTML/Element/blockquote\"><code><blockquote></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/body\"><code><body></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/br\"><code><br></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/button\"><code><button></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/canvas\"><code><canvas></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/caption\"><code><caption></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/center\"><code><center></code></a><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTML/Element/cite\"><code><cite></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/code\"><code><code></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/col\"><code><col></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/colgroup\"><code><colgroup></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/data\"><code><data></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/datalist\"><code><datalist></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/dd\"><code><dd></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/del\"><code><del></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/details\"><code><details></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/dfn\"><code><dfn></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/dialog\"><code><dialog></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/dir\"><code><dir></code></a><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTML/Element/div\"><code><div></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/dl\"><code><dl></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/dt\"><code><dt></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/em\"><code><em></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/embed\"><code><embed></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/fencedframe\"><code><fencedframe></code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTML/Element/fieldset\"><code><fieldset></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/figcaption\"><code><figcaption></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/figure\"><code><figure></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/font\"><code><font></code></a><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTML/Element/footer\"><code><footer></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/form\"><code><form></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/frame\"><code><frame></code></a><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTML/Element/frameset\"><code><frameset></code></a><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTML/Element/Heading_Elements\"><code><h1></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/head\"><code><head></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/header\"><code><header></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/hgroup\"><code><hgroup></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/hr\"><code><hr></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/html\"><code><html></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/i\"><code><i></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/iframe\"><code><iframe></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/img\"><code><img></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/input\"><code><input></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/ins\"><code><ins></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/kbd\"><code><kbd></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/label\"><code><label></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/legend\"><code><legend></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/li\"><code><li></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/link\"><code><link></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/main\"><code><main></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/map\"><code><map></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/mark\"><code><mark></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/marquee\"><code><marquee></code></a><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTML/Element/menu\"><code><menu></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/meta\"><code><meta></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/meter\"><code><meter></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/nav\"><code><nav></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/nobr\"><code><nobr></code></a><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTML/Element/noembed\"><code><noembed></code></a><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTML/Element/noframes\"><code><noframes></code></a><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTML/Element/noscript\"><code><noscript></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/object\"><code><object></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/ol\"><code><ol></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/optgroup\"><code><optgroup></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/option\"><code><option></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/output\"><code><output></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/p\"><code><p></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/param\"><code><param></code></a><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTML/Element/picture\"><code><picture></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/plaintext\"><code><plaintext></code></a><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTML/Element/portal\"><code><portal></code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTML/Element/pre\"><code><pre></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/progress\"><code><progress></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/q\"><code><q></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/rb\"><code><rb></code></a><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTML/Element/rp\"><code><rp></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/rt\"><code><rt></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/rtc\"><code><rtc></code></a><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTML/Element/ruby\"><code><ruby></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/s\"><code><s></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/samp\"><code><samp></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/script\"><code><script></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/search\"><code><search></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/section\"><code><section></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/select\"><code><select></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/slot\"><code><slot></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/small\"><code><small></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/source\"><code><source></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/span\"><code><span></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/strike\"><code><strike></code></a><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTML/Element/strong\"><code><strong></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/style\"><code><style></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/sub\"><code><sub></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/summary\"><code><summary></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/sup\"><code><sup></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/table\"><code><table></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/tbody\"><code><tbody></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/td\"><code><td></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/template\"><code><template></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/textarea\"><code><textarea></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/tfoot\"><code><tfoot></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/th\"><code><th></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/thead\"><code><thead></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/time\"><code><time></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/title\"><code><title></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/tr\"><code><tr></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/track\"><code><track></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/tt\"><code><tt></code></a><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTML/Element/u\"><code><u></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/ul\"><code><ul></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/var\"><code><var></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/video\"><code><video></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/wbr\"><code><wbr></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/xmp\"><code><xmp></code></a><abbr class=\"icon icon-deprecated\" title=\"Deprecated. Not for use in new websites.\">\n <span class=\"visually-hidden\">Deprecated</span>\n</abbr></li></ol>\n </details>\n </li>\n <li class=\"toggle\">\n <details>\n <summary>Global attributes</summary>\n <ol><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/accesskey\"><code>accesskey</code></a></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/anchor\"><code>anchor</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr><abbr class=\"icon icon-nonstandard\" title=\"Non-standard. Check cross-browser support before using.\">\n <span class=\"visually-hidden\">Non-standard</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/autocapitalize\"><code>autocapitalize</code></a></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/autocorrect\"><code>autocorrect</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/autofocus\"><code>autofocus</code></a></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/class\"><code>class</code></a></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/contenteditable\"><code>contenteditable</code></a></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/data-*\"><code>data-*</code></a></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/dir\"><code>dir</code></a></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/draggable\"><code>draggable</code></a></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/enterkeyhint\"><code>enterkeyhint</code></a></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/exportparts\"><code>exportparts</code></a></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/hidden\"><code>hidden</code></a></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/id\"><code>id</code></a></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/inert\"><code>inert</code></a></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/inputmode\"><code>inputmode</code></a></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/is\"><code>is</code></a></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/itemid\"><code>itemid</code></a></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/itemprop\"><code>itemprop</code></a></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/itemref\"><code>itemref</code></a></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/itemscope\"><code>itemscope</code></a></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/itemtype\"><code>itemtype</code></a></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/lang\"><code>lang</code></a></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/nonce\"><code>nonce</code></a></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/part\"><code>part</code></a></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/popover\"><code>popover</code></a></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/slot\"><code>slot</code></a></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/spellcheck\"><code>spellcheck</code></a></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/style\"><code>style</code></a></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/tabindex\"><code>tabindex</code></a></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/title\"><code>title</code></a></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/translate\"><code>translate</code></a></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/virtualkeyboardpolicy\"><code>virtualkeyboardpolicy</code></a><abbr class=\"icon icon-experimental\" title=\"Experimental. Expect behavior to change in the future.\">\n <span class=\"visually-hidden\">Experimental</span>\n</abbr></li><li><a href=\"/en-US/docs/Web/HTML/Global_attributes/writingsuggestions\"><code>writingsuggestions</code></a></li></ol>\n </details>\n </li>\n <li class=\"toggle\">\n <details open=\"\">\n <summary>Attributes</summary>\n <ol>\n \n <li><a href=\"/en-US/docs/Web/HTML/Attributes/accept\">accept</a></li>\n \n <li><a href=\"/en-US/docs/Web/HTML/Attributes/autocomplete\">autocomplete</a></li>\n \n <li><a href=\"/en-US/docs/Web/HTML/Attributes/capture\">capture</a></li>\n \n <li><a href=\"/en-US/docs/Web/HTML/Attributes/crossorigin\">crossorigin</a></li>\n \n <li><a href=\"/en-US/docs/Web/HTML/Attributes/dirname\">dirname</a></li>\n \n <li><a href=\"/en-US/docs/Web/HTML/Attributes/disabled\">disabled</a></li>\n \n <li><a href=\"/en-US/docs/Web/HTML/Attributes/elementtiming\">elementtiming</a></li>\n \n <li><a href=\"/en-US/docs/Web/HTML/Attributes/for\">for</a></li>\n \n <li><a href=\"/en-US/docs/Web/HTML/Attributes/max\">max</a></li>\n \n <li><a href=\"/en-US/docs/Web/HTML/Attributes/maxlength\">maxlength</a></li>\n \n <li><a href=\"/en-US/docs/Web/HTML/Attributes/min\">min</a></li>\n \n <li><a href=\"/en-US/docs/Web/HTML/Attributes/minlength\">minlength</a></li>\n \n <li><a href=\"/en-US/docs/Web/HTML/Attributes/multiple\">multiple</a></li>\n \n <li><em><a href=\"/en-US/docs/Web/HTML/Attributes/pattern\" aria-current=\"page\">pattern</a></em></li>\n \n <li><a href=\"/en-US/docs/Web/HTML/Attributes/placeholder\">placeholder</a></li>\n \n <li><a href=\"/en-US/docs/Web/HTML/Attributes/readonly\">readonly</a></li>\n \n <li><a href=\"/en-US/docs/Web/HTML/Attributes/rel\">rel</a></li>\n \n <li><a href=\"/en-US/docs/Web/HTML/Attributes/required\">required</a></li>\n \n <li><a href=\"/en-US/docs/Web/HTML/Attributes/size\">size</a></li>\n \n <li><a href=\"/en-US/docs/Web/HTML/Attributes/step\">step</a></li>\n \n </ol>\n </details>\n </li>\n <li class=\"toggle\">\n <details>\n <summary><code><input></code> types</summary>\n <ol><li><a href=\"/en-US/docs/Web/HTML/Element/input/button\"><code><input type=\"button\"></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/input/checkbox\"><code><input type=\"checkbox\"></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/input/color\"><code><input type=\"color\"></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/input/date\"><code><input type=\"date\"></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/input/datetime-local\"><code><input type=\"datetime-local\"></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/input/email\"><code><input type=\"email\"></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/input/file\"><code><input type=\"file\"></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/input/hidden\"><code><input type=\"hidden\"></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/input/image\"><code><input type=\"image\"></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/input/month\"><code><input type=\"month\"></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/input/number\"><code><input type=\"number\"></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/input/password\"><code><input type=\"password\"></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/input/radio\"><code><input type=\"radio\"></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/input/range\"><code><input type=\"range\"></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/input/reset\"><code><input type=\"reset\"></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/input/search\"><code><input type=\"search\"></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/input/submit\"><code><input type=\"submit\"></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/input/tel\"><code><input type=\"tel\"></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/input/text\"><code><input type=\"text\"></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/input/time\"><code><input type=\"time\"></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/input/url\"><code><input type=\"url\"></code></a></li><li><a href=\"/en-US/docs/Web/HTML/Element/input/week\"><code><input type=\"week\"></code></a></li></ol>\n </details>\n </li>\n <li class=\"section no-link\">Guides</li>\n <li>\n <ol>\n <li><a href=\"/en-US/docs/Web/HTML/Content_categories\">Content categories</a></li>\n <li><a href=\"/en-US/docs/Glossary/Block-level_content\">Block-level elements</a></li>\n <li><a href=\"/en-US/docs/Glossary/Inline-level_content\">Inline elements</a></li>\n <li><a href=\"/en-US/docs/Web/HTML/Quirks_Mode_and_Standards_Mode\">Quirks Mode and Standards Mode</a></li>\n <li><a href=\"/en-US/docs/Web/HTML/Date_and_time_formats\">Date and time formats used in HTML</a></li>\n <li><a href=\"/en-US/docs/Web/HTML/Constraint_validation\">Constraint validation</a></li>\n <li><a href=\"/en-US/docs/Web/HTML/Microdata\">Microdata</a></li>\n <li><a href=\"/en-US/docs/Web/HTML/microformats\">Microformats</a></li>\n <li><a href=\"/en-US/docs/Web/HTML/Viewport_meta_tag\">Viewport meta tag</a></li>\n <li><a href=\"/en-US/docs/Web/HTML/CORS_enabled_image\">Allowing cross-origin use of images and canvas</a></li>\n </ol>\n </li>\n </ol>\n","sidebarMacro":"HTMLSidebar","body":[{"type":"prose","value":{"id":null,"title":null,"isH3":false,"content":"<p>The <strong><code>pattern</code></strong> attribute specifies a <a href=\"/en-US/docs/Web/JavaScript/Guide/Regular_expressions\">regular expression</a> the form control's value should match. If a non-<code>null</code> value doesn't conform to the constraints set by the <code>pattern</code> value, the <a href=\"/en-US/docs/Web/API/ValidityState\"><code>ValidityState</code></a> object's read-only <a href=\"/en-US/docs/Web/API/ValidityState/patternMismatch\" title=\"patternMismatch\"><code>patternMismatch</code></a> property will be true.</p>"}},{"type":"prose","value":{"id":"try_it","title":"Try it","isH3":false,"content":"<iframe class=\"interactive is-tabbed-shorter-height\" height=\"200\" src=\"https://interactive-examples.mdn.mozilla.net/pages/tabbed/attribute-pattern.html\" title=\"MDN Web Docs Interactive Example\" allow=\"clipboard-write\" loading=\"lazy\"></iframe>"}},{"type":"prose","value":{"id":"overview","title":"Overview","isH3":false,"content":"<p>The <code>pattern</code> attribute is an attribute of the <a href=\"/en-US/docs/Web/HTML/Element/input/text\">text</a>, <a href=\"/en-US/docs/Web/HTML/Element/input/tel\">tel</a>, <a href=\"/en-US/docs/Web/HTML/Element/input/email\">email</a>, <a href=\"/en-US/docs/Web/HTML/Element/input/url\">url</a>, <a href=\"/en-US/docs/Web/HTML/Element/input/password\">password</a>, and <a href=\"/en-US/docs/Web/HTML/Element/input/search\">search</a> input types.</p>\n<p>The <code>pattern</code> attribute, when specified, is a regular expression which the input's <a href=\"/en-US/docs/Web/HTML/Element/input#value\"><code>value</code></a> must match for the value to pass <a href=\"/en-US/docs/Web/HTML/Constraint_validation\">constraint validation</a>. It must be a valid JavaScript regular expression, as used by the <a href=\"/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp\"><code>RegExp</code></a> type, and as documented in our <a href=\"/en-US/docs/Web/JavaScript/Guide/Regular_expressions\">guide on regular expressions</a>.</p>\n<p>The pattern's regular expression is compiled with the <a href=\"/en-US/docs/Web/JavaScript/Reference/Regular_expressions/Character_class#v-mode_character_class\"><code>'v'</code> flag</a>. This makes the regular expression <a href=\"/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/unicode#unicode-aware_mode\">unicode-aware</a>, and also changes how character classes are interpreted. This allows character class set intersection and subtraction operations, and in addition to <code>]</code> and <code>\\</code>, the following characters must be escaped using a <code>\\</code> backslash if they represent literal characters: <code>(</code>, <code>)</code>, <code>[</code>, <code>{</code>, <code>}</code>, <code>/</code>, <code>-</code>, <code>|</code>. Before mid-2023, the <code>'u'</code> flag was specified instead; If you're updating older code, <a href=\"https://github.com/tc39/proposal-regexp-v-flag#how-is-the-v-flag-different-from-the-u-flag\" class=\"external\" target=\"_blank\">this document outlines the differences</a>.</p>\n<p>The pattern's regular expression must match the entire input's <code>value</code>, rather than matching a substring - as if a <code>^(?:</code> were implied at the start of the pattern and <code>)$</code> at the end.</p>\n<p>No forward slashes should be specified around the pattern text. No regular expression is applied if the attribute value is absent, an empty string, or invalid.</p>\n<p>Some of the input types supporting the pattern attribute, notably the <a href=\"/en-US/docs/Web/HTML/Element/input/email\">email</a> and <a href=\"/en-US/docs/Web/HTML/Element/input/url\">url</a> input types, have expected value syntaxes that must be matched. If the pattern attribute isn't present, and the value doesn't match the expected syntax for that value type, the <a href=\"/en-US/docs/Web/API/ValidityState\"><code>ValidityState</code></a> object's read-only <a href=\"/en-US/docs/Web/API/ValidityState/typeMismatch\" title=\"typeMismatch\"><code>typeMismatch</code></a> property will be true.</p>"}},{"type":"prose","value":{"id":"constraint_validation","title":"Constraint validation","isH3":true,"content":"<p>If the input's value is not the empty string and the value does not match the entire regular expression, there is a constraint violation reported by the <a href=\"/en-US/docs/Web/API/ValidityState\"><code>ValidityState</code></a> object's <a href=\"/en-US/docs/Web/API/ValidityState/patternMismatch\" title=\"patternMismatch\"><code>patternMismatch</code></a> property being <code>true</code>.</p>\n<div class=\"notecard note\">\n <p><strong>Note:</strong> If the <code>pattern</code> attribute is specified with no value, its value is implicitly the empty string. Thus, <strong>any non-empty</strong> input <code>value</code> will result in constraint violation.</p>\n</div>"}},{"type":"prose","value":{"id":"usability_and_accessibility_considerations","title":"Usability and accessibility considerations","isH3":true,"content":"<p>When including a <code>pattern</code>, provide a description of the pattern in visible text near the control. Additionally, include a <a href=\"/en-US/docs/Web/HTML/Element/input#title\"><code>title</code></a> attribute which gives a description of the pattern. User agents may use the title contents during constraint validation to tell the user that the pattern is not matched. Some browsers show a tooltip with title contents, improving usability for sighted users. Additionally, assistive technology may read the title aloud when the control gains focus, but this should not be relied upon for accessibility.</p>\n<p>Only relying on the <code>title</code> attribute for the visual display of text content is discouraged, as many user agents do not expose the attribute in an accessible manner. Although some browsers show a tooltip when an element with a title is hovered, that leaves out keyboard-only and touch-only users. This is one of the several reasons you must include information informing users how to fill out the control to match the requirements.</p>\n<p>While <code>title</code>s are used by some browsers to populate error messaging, because browsers sometimes also show the title as text on hover, it therefore shows in non-error situations, so be careful not to word titles as if an error has occurred.</p>"}},{"type":"prose","value":{"id":"examples","title":"Examples","isH3":false,"content":""}},{"type":"prose","value":{"id":"matching_a_phone_number","title":"Matching a phone number","isH3":true,"content":"<p>Given the following:</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">html</span></div><pre class=\"brush: html notranslate\"><code><p>\n <label>\n Enter your phone number in the format (123) - 456 - 7890 (<input\n name=\"tel1\"\n type=\"tel\"\n pattern=\"[0-9]{3}\"\n placeholder=\"###\"\n aria-label=\"3-digit area code\"\n size=\"2\" />) -\n <input\n name=\"tel2\"\n type=\"tel\"\n pattern=\"[0-9]{3}\"\n placeholder=\"###\"\n aria-label=\"3-digit prefix\"\n size=\"2\" />\n -\n <input\n name=\"tel3\"\n type=\"tel\"\n pattern=\"[0-9]{4}\"\n placeholder=\"####\"\n aria-label=\"4-digit number\"\n size=\"3\" />\n </label>\n</p>\n</code></pre></div>\n<p>Here we have 3 sections for a north American phone number with an implicit label encompassing all three components of the phone number, expecting 3-digits, 3-digits and 4-digits respectively, as defined by the <code>pattern</code> attribute set on each.</p>\n<p>If the values are too long or too short, or contain characters that aren't digits, the <code>patternMismatch</code> will be true. When <code>true</code>, the element matches the <a href=\"/en-US/docs/Web/CSS/:invalid\"><code>:invalid</code></a> CSS pseudo-classes.</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">css</span></div><pre class=\"brush: css notranslate\"><code>input:invalid {\n border: red solid 3px;\n}\n</code></pre></div><div class=\"code-example\"><div class=\"example-header\"></div><iframe class=\"sample-code-frame\" title=\"Matching a phone number sample\" id=\"frame_matching_a_phone_number\" width=\"300\" height=\"80\" src=\"about:blank\" data-live-path=\"/en-US/docs/Web/HTML/Attributes/pattern\" data-live-id=\"matching_a_phone_number\" sandbox=\"allow-same-origin allow-scripts\" loading=\"lazy\"></iframe></div>\n<p>If we had used <a href=\"/en-US/docs/Web/HTML/Attributes/minlength\"><code>minlength</code></a> and <a href=\"/en-US/docs/Web/HTML/Attributes/maxlength\"><code>maxlength</code></a> attributes instead, we may have seen <a href=\"/en-US/docs/Web/API/ValidityState/tooLong\"><code>validityState.tooLong</code></a> or <a href=\"/en-US/docs/Web/API/ValidityState/tooShort\"><code>validityState.tooShort</code></a> being true.</p>"}},{"type":"prose","value":{"id":"specifying_a_pattern","title":"Specifying a pattern","isH3":true,"content":"<p>You can use the <a href=\"/en-US/docs/Web/HTML/Element/input#pattern\"><code>pattern</code></a> attribute to specify a regular expression that the inputted value must match in order to be considered valid (see <a href=\"/en-US/docs/Learn/Forms/Form_validation#validating_against_a_regular_expression\">Validating against a regular expression</a> for a crash course on using regular expressions to validate inputs).</p>\n<p>The example below restricts the value to 4-8 characters and requires that it contain only lower-case letters.</p>\n<div class=\"code-example\"><div class=\"example-header\"><span class=\"language-name\">html</span></div><pre class=\"brush: html notranslate\"><code><form>\n <div>\n <label for=\"uname\">Choose a username: </label>\n <input\n type=\"text\"\n id=\"uname\"\n name=\"name\"\n required\n size=\"45\"\n pattern=\"[a-z]{4,8}\"\n title=\"4 to 8 lowercase letters\" />\n <span class=\"validity\"></span>\n <p>Usernames must be lowercase and 4-8 characters in length.</p>\n </div>\n <div>\n <button>Submit</button>\n </div>\n</form>\n</code></pre></div>\n<div class=\"code-example\"><pre class=\"brush: css hidden notranslate\"><code>div {\n margin-bottom: 10px;\n position: relative;\n}\n\np {\n font-size: 80%;\n color: #999;\n}\n\ninput + span {\n padding-right: 30px;\n}\n\ninput:invalid + span::after {\n position: absolute;\n content: \"✖\";\n padding-left: 5px;\n}\n\ninput:valid + span::after {\n position: absolute;\n content: \"✓\";\n padding-left: 5px;\n}\n</code></pre></div>\n<p>This renders like so:</p><div class=\"code-example\"><div class=\"example-header\"></div><iframe class=\"sample-code-frame\" title=\"Specifying a pattern sample\" id=\"frame_specifying_a_pattern\" width=\"600\" height=\"110\" src=\"about:blank\" data-live-path=\"/en-US/docs/Web/HTML/Attributes/pattern\" data-live-id=\"specifying_a_pattern\" sandbox=\"allow-same-origin allow-scripts\" loading=\"lazy\"></iframe></div>"}},{"type":"specifications","value":{"title":"Specifications","id":"specifications","isH3":false,"specifications":[{"bcdSpecificationURL":"https://html.spec.whatwg.org/multipage/input.html#attr-input-pattern","title":"HTML Standard"}],"query":"html.elements.input.pattern"}},{"type":"browser_compatibility","value":{"title":"Browser compatibility","id":"browser_compatibility","isH3":false,"query":"html.elements.input.pattern"}},{"type":"prose","value":{"id":"see_also","title":"See also","isH3":false,"content":"<ul>\n <li><a href=\"/en-US/docs/Web/HTML/Constraint_validation\">Constraint validation</a></li>\n <li><a href=\"/en-US/docs/Learn/Forms/Form_validation\">Forms: Data form validation</a></li>\n <li><a href=\"/en-US/docs/Web/JavaScript/Guide/Regular_expressions\">Regular Expressions</a></li>\n</ul>"}}],"toc":[{"text":"Try it","id":"try_it"},{"text":"Overview","id":"overview"},{"text":"Examples","id":"examples"},{"text":"Specifications","id":"specifications"},{"text":"Browser compatibility","id":"browser_compatibility"},{"text":"See also","id":"see_also"}],"summary":"The pattern attribute specifies a regular expression the form control's value should match. If a non-null value doesn't conform to the constraints set by the pattern value, the ValidityState object's read-only patternMismatch property will be true.","popularity":0.0078,"modified":"2024-11-21T09:46:52.000Z","other_translations":[{"locale":"de","title":"HTML-Attribut: pattern","native":"Deutsch"},{"locale":"fr","title":"Attribut HTML : pattern","native":"Français"},{"locale":"ja","title":"HTML 属性: pattern","native":"日本語"},{"locale":"ru","title":"HTML attribute: pattern","native":"Русский"},{"locale":"zh-CN","title":"HTML 属性：pattern","native":"中文 (简体)"}],"pageType":"html-attribute","source":{"folder":"en-us/web/html/attributes/pattern","github_url":"https://github.com/mdn/content/blob/main/files/en-us/web/html/attributes/pattern/index.md","last_commit_url":"https://github.com/mdn/content/commit/4d3605197ea5c6407aacca2a80cc27a398f04fc8","filename":"index.md"},"short_title":"pattern","parents":[{"uri":"/en-US/docs/Web","title":"References"},{"uri":"/en-US/docs/Web/HTML","title":"HTML"},{"uri":"/en-US/docs/Web/HTML/Attributes","title":"Attributes"},{"uri":"/en-US/docs/Web/HTML/Attributes/pattern","title":"pattern"}],"pageTitle":"HTML attribute: pattern - HTML: HyperText Markup Language | MDN","noIndexing":false}}</script></body></html>