CINXE.COM

<!DOCTYPE html> <html class="client-nojs vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-sticky-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-disabled skin-theme-clientpref-day vector-toc-not-available" lang="en" dir="ltr"> <head> <meta charset="UTF-8"> <title>JavaScript - Wikibooks, open books for an open world</title> <script>(function(){var className="client-js vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-sticky-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-disabled skin-theme-clientpref-day vector-toc-not-available";var cookie=document.cookie.match(/(?:^|; )enwikibooksmwclientpreferences=([^;]+)/);if(cookie){cookie[1].split('%2C').forEach(function(pref){className=className.replace(new RegExp('(^| )'+pref.replace(/-clientpref-\w+$|[^\w-]+/g,'')+'-clientpref-\\w+( |$)'),'$1'+pref+'$2');});}document.documentElement.className=className;}());RLCONF={"wgBreakFrames":false,"wgSeparatorTransformTable":["",""],"wgDigitTransformTable":["",""], "wgDefaultDateFormat":"dmy","wgMonthNames":["","January","February","March","April","May","June","July","August","September","October","November","December"],"wgRequestId":"534f5f43-55a8-4fb6-a954-4f136f2c3170","wgCanonicalNamespace":"","wgCanonicalSpecialPageName":false,"wgNamespaceNumber":0,"wgPageName":"JavaScript","wgTitle":"JavaScript","wgCurRevisionId":4416493,"wgRevisionId":4416493,"wgArticleId":10884,"wgIsArticle":true,"wgIsRedirect":false,"wgAction":"view","wgUserName":null,"wgUserGroups":["*"],"wgCategories":["Books with print version","Books with PDF version","Subject:JavaScript scripting language","Subject:JavaScript scripting language/all books","Subject:Scripting languages/all books","Subject:Computer programming languages/all books","Subject:Computer programming/all books","Subject:Computer science/all books","Subject:Computing/all books","Subject:Books by subject/all books","Subject:Web development/all books","Subject:Internet/all books","Book:Wikibooks Stacks/Books", "Shelf:JavaScript scripting language/all books","Shelf:Computer programming/all books","Shelf:Computer programming languages/all books","Shelf:Computer science/all books","Department:Computing/all books","Shelf:Internet/all books","Shelf:Scripting languages/all books","Shelf:Web development/all books","Alphabetical/J","Half-finished books","Books by completion status/all books","Book:JavaScript","Shelf:JavaScript scripting language"],"wgPageViewLanguage":"en","wgPageContentLanguage":"en","wgPageContentModel":"wikitext","wgRelevantPageName":"JavaScript","wgRelevantArticleId":10884,"wgIsProbablyEditable":true,"wgRelevantPageIsProbablyEditable":true,"wgRestrictionEdit":[],"wgRestrictionMove":[],"wgNoticeProject":"wikibooks","wgCiteReferencePreviewsActive":true,"wgFlaggedRevsParams":{"tags":{"value":{"levels":3}}},"wgStableRevisionId":4416493,"wgMediaViewerOnClick":true,"wgMediaViewerEnabledByDefault":true,"wgVisualEditor":{"pageLanguageCode":"en","pageLanguageDir":"ltr", "pageVariantFallbacks":"en"},"wgMFDisplayWikibaseDescriptions":{"search":true,"watchlist":true,"tagline":false,"nearby":true},"wgWMESchemaEditAttemptStepOversample":false,"wgWMEPageLength":3000,"wgCentralAuthMobileDomain":false,"wgEditSubmitButtonLabelPublish":true,"wgULSPosition":"interlanguage","wgULSisCompactLinksEnabled":false,"wgVector2022LanguageInHeader":true,"wgULSisLanguageSelectorEmpty":false,"wgWikibaseItemId":"Q2005","wgCheckUserClientHintsHeadersJsApi":["brands","architecture","bitness","fullVersionList","mobile","model","platform","platformVersion"],"wgSiteNoticeId":"2.24"};RLSTATE={"ext.globalCssJs.user.styles":"ready","site.styles":"ready","user.styles":"ready","ext.globalCssJs.user":"ready","user":"ready","user.options":"loading","ext.inputBox.styles":"ready","skins.vector.search.codex.styles":"ready","skins.vector.styles":"ready","skins.vector.icons":"ready","ext.flaggedRevs.basic":"ready","mediawiki.codex.messagebox.styles":"ready","ext.wikimediamessages.styles": "ready","ext.visualEditor.desktopArticleTarget.noscript":"ready","ext.uls.interlanguage":"ready","wikibase.client.init":"ready","ext.wikimediaBadges":"ready","ext.dismissableSiteNotice.styles":"ready"};RLPAGEMODULES=["site","mediawiki.page.ready","skins.vector.js","ext.centralNotice.geoIP","ext.centralNotice.startUp","ext.flaggedRevs.advanced","ext.gadget.wikidialog","ext.gadget.commons-file","ext.urlShortener.toolbar","ext.centralauth.centralautologin","mmv.bootstrap","ext.visualEditor.desktopArticleTarget.init","ext.visualEditor.targetLoader","ext.echo.centralauth","ext.eventLogging","ext.wikimediaEvents","ext.navigationTiming","ext.uls.interface","wikibase.client.vector-2022","ext.checkUser.clientHints","wikibase.sidebar.tracking","ext.dismissableSiteNotice"];</script> <script>(RLQ=window.RLQ||[]).push(function(){mw.loader.impl(function(){return["user.options@12s5i",function($,jQuery,require,module){mw.user.tokens.set({"patrolToken":"+\\","watchToken":"+\\","csrfToken":"+\\"}); }];});});</script> <link rel="stylesheet" href="/w/load.php?lang=en&modules=ext.dismissableSiteNotice.styles%7Cext.flaggedRevs.basic%7Cext.inputBox.styles%7Cext.uls.interlanguage%7Cext.visualEditor.desktopArticleTarget.noscript%7Cext.wikimediaBadges%7Cext.wikimediamessages.styles%7Cmediawiki.codex.messagebox.styles%7Cskins.vector.icons%2Cstyles%7Cskins.vector.search.codex.styles%7Cwikibase.client.init&only=styles&skin=vector-2022"> <script async="" src="/w/load.php?lang=en&modules=startup&only=scripts&raw=1&skin=vector-2022"></script> <meta name="ResourceLoaderDynamicStyles" content=""> <link rel="stylesheet" href="/w/load.php?lang=en&modules=site.styles&only=styles&skin=vector-2022"> <meta name="generator" content="MediaWiki 1.44.0-wmf.4"> <meta name="referrer" content="origin"> <meta name="referrer" content="origin-when-cross-origin"> <meta name="robots" content="max-image-preview:standard"> <meta name="format-detection" content="telephone=no"> <meta name="viewport" content="width=1120"> <meta property="og:title" content="JavaScript - Wikibooks, open books for an open world"> <meta property="og:type" content="website"> <link rel="preconnect" href="//upload.wikimedia.org"> <link rel="alternate" media="only screen and (max-width: 640px)" href="//en.m.wikibooks.org/wiki/JavaScript"> <link rel="alternate" type="application/x-wiki" title="Edit" href="/w/index.php?title=JavaScript&action=edit"> <link rel="icon" href="/static/favicon/wikibooks.ico"> <link rel="search" type="application/opensearchdescription+xml" href="/w/rest.php/v1/search" title="Wikibooks (en)"> <link rel="EditURI" type="application/rsd+xml" href="//en.wikibooks.org/w/api.php?action=rsd"> <link rel="canonical" href="https://en.wikibooks.org/wiki/JavaScript"> <link rel="license" href="https://creativecommons.org/licenses/by-sa/4.0/deed.en"> <link rel="alternate" type="application/atom+xml" title="Wikibooks Atom feed" href="/w/index.php?title=Special:RecentChanges&feed=atom"> <link rel="dns-prefetch" href="//meta.wikimedia.org" /> <link rel="dns-prefetch" href="//login.wikimedia.org"> </head> <body class="skin--responsive skin-vector skin-vector-search-vue mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject mw-editable page-JavaScript rootpage-JavaScript skin-vector-2022 action-view"><a class="mw-jump-link" href="#bodyContent">Jump to content</a> <div class="vector-header-container"> <header class="vector-header mw-header"> <div class="vector-header-start"> <nav class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-dropdown" class="vector-dropdown vector-main-menu-dropdown vector-button-flush-left vector-button-flush-right" > <input type="checkbox" id="vector-main-menu-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-main-menu-dropdown" class="vector-dropdown-checkbox " aria-label="Main menu" > <label id="vector-main-menu-dropdown-label" for="vector-main-menu-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-menu mw-ui-icon-wikimedia-menu"></span> <span class="vector-dropdown-label-text">Main menu</span> </label> <div class="vector-dropdown-content"> <div id="vector-main-menu-unpinned-container" class="vector-unpinned-container"> <div id="vector-main-menu" class="vector-main-menu vector-pinnable-element"> <div class="vector-pinnable-header vector-main-menu-pinnable-header vector-pinnable-header-unpinned" data-feature-name="main-menu-pinned" data-pinnable-element-id="vector-main-menu" data-pinned-container-id="vector-main-menu-pinned-container" data-unpinned-container-id="vector-main-menu-unpinned-container" > <div class="vector-pinnable-header-label">Main menu</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-main-menu.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-main-menu.unpin">hide</button> </div> <div id="p-navigation" class="vector-menu mw-portlet mw-portlet-navigation" > <div class="vector-menu-heading"> Navigation </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-mainpage" class="mw-list-item"><a href="/wiki/Main_Page" title="Visit the main page [z]" accesskey="z"><span>Main Page</span></a></li><li id="n-help" class="mw-list-item"><a href="/wiki/Help:Contents" title="Find help on how to use and edit Wikibooks"><span>Help</span></a></li><li id="n-Browse" class="mw-list-item"><a href="/wiki/Wikibooks:Card_Catalog_Office" title="Check out what Wikibooks has to offer"><span>Browse</span></a></li><li id="n-Cookbook" class="mw-list-item"><a href="/wiki/Cookbook:Table_of_Contents" title="Learn recipes from around the world"><span>Cookbook</span></a></li><li id="n-Wikijunior" class="mw-list-item"><a href="/wiki/Wikijunior" title="Books for children"><span>Wikijunior</span></a></li><li id="n-Featured-books" class="mw-list-item"><a href="/wiki/Wikibooks:Featured_books" title="The best of Wikibooks"><span>Featured books</span></a></li><li id="n-recentchanges" class="mw-list-item"><a href="/wiki/Special:RecentChanges" title="A list of recent changes in the wiki [r]" accesskey="r"><span>Recent changes</span></a></li><li id="n-randomrootpage" class="mw-list-item"><a href="/wiki/Special:RandomInCategory/Book:Wikibooks_Stacks/Books"><span>Random book</span></a></li><li id="n-Using-Wikibooks" class="mw-list-item"><a href="/wiki/Using_Wikibooks"><span>Using Wikibooks</span></a></li> </ul> </div> </div> <div id="p-community" class="vector-menu mw-portlet mw-portlet-community" > <div class="vector-menu-heading"> Community </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-Reading-room-forum" class="mw-list-item"><a href="/wiki/Wikibooks:Reading_room"><span>Reading room forum</span></a></li><li id="n-portal" class="mw-list-item"><a href="/wiki/Wikibooks:Community_Portal" title="Find your way around the Wikibooks community"><span>Community portal</span></a></li><li id="n-currentevents" class="mw-list-item"><a href="/wiki/Wikibooks:Reading_room/Bulletin_Board" title="Important community news"><span>Bulletin Board</span></a></li><li id="n-maintenance" class="mw-list-item"><a href="/wiki/Wikibooks:Maintenance" title="Frequent tasks that you can help with"><span>Help out!</span></a></li><li id="n-Policies-and-guidelines" class="mw-list-item"><a href="/wiki/Wikibooks:Policies_and_guidelines" title="Pages detailing important rules and procedures"><span>Policies and guidelines</span></a></li><li id="n-contact" class="mw-list-item"><a href="/wiki/Wikibooks:Contact_us" title="Alternative methods of communication"><span>Contact us</span></a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> <a href="/wiki/Main_Page" class="mw-logo"> <img class="mw-logo-icon" src="/static/images/icons/wikibooks.svg" alt="" aria-hidden="true" height="50" width="50"> <span class="mw-logo-container skin-invert"> <img class="mw-logo-wordmark" alt="Wikibooks" src="/static/images/mobile/copyright/wikibooks-wordmark-vi.svg" style="width: 7.5em; height: 0.9375em;"> <img class="mw-logo-tagline" alt="The Free Textbook Project" src="/static/images/mobile/copyright/wikibooks-tagline-en.svg" width="120" height="10" style="width: 7.5em; height: 0.625em;"> </span> </a> </div> <div class="vector-header-end"> <div id="p-search" role="search" class="vector-search-box-vue vector-search-box-collapses vector-search-box-show-thumbnail vector-search-box-auto-expand-width vector-search-box"> <a href="/wiki/Special:Search" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only search-toggle" title="Search Wikibooks [f]" accesskey="f"><span class="vector-icon mw-ui-icon-search mw-ui-icon-wikimedia-search"></span> <span>Search</span> </a> <div class="vector-typeahead-search-container"> <div class="cdx-typeahead-search cdx-typeahead-search--show-thumbnail cdx-typeahead-search--auto-expand-width"> <form action="/w/index.php" id="searchform" class="cdx-search-input cdx-search-input--has-end-button"> <div id="simpleSearch" class="cdx-search-input__input-wrapper" data-search-loc="header-moved"> <div class="cdx-text-input cdx-text-input--has-start-icon"> <input class="cdx-text-input__input" type="search" name="search" placeholder="Search Wikibooks" aria-label="Search Wikibooks" autocapitalize="sentences" title="Search Wikibooks [f]" accesskey="f" id="searchInput" > <span class="cdx-text-input__icon cdx-text-input__start-icon"></span> </div> <input type="hidden" name="title" value="Special:Search"> </div> <button class="cdx-button cdx-search-input__end-button">Search</button> </form> </div> </div> </div> <nav class="vector-user-links vector-user-links-wide" aria-label="Personal tools"> <div class="vector-user-links-main"> <div id="p-vector-user-menu-preferences" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-userpage" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <nav class="vector-appearance-landmark" aria-label="Appearance"> <div id="vector-appearance-dropdown" class="vector-dropdown " title="Change the appearance of the page's font size, width, and color" > <input type="checkbox" id="vector-appearance-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-appearance-dropdown" class="vector-dropdown-checkbox " aria-label="Appearance" > <label id="vector-appearance-dropdown-label" for="vector-appearance-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-appearance mw-ui-icon-wikimedia-appearance"></span> <span class="vector-dropdown-label-text">Appearance</span> </label> <div class="vector-dropdown-content"> <div id="vector-appearance-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <div id="p-vector-user-menu-notifications" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-overflow" class="vector-menu mw-portlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="//donate.wikimedia.org/wiki/Special:FundraiserRedirector?utm_source=donate&utm_medium=sidebar&utm_campaign=C13_en.wikibooks.org&uselang=en" class=""><span>Donations</span></a> </li> <li id="pt-createaccount-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:CreateAccount&returnto=JavaScript" title="You are encouraged to create an account and log in; however, it is not mandatory" class=""><span>Create account</span></a> </li> <li id="pt-login-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:UserLogin&returnto=JavaScript" title="You are encouraged to log in; however, it is not mandatory [o]" accesskey="o" class=""><span>Log in</span></a> </li> </ul> </div> </div> </div> <div id="vector-user-links-dropdown" class="vector-dropdown vector-user-menu vector-button-flush-right vector-user-menu-logged-out" title="More options" > <input type="checkbox" id="vector-user-links-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-user-links-dropdown" class="vector-dropdown-checkbox " aria-label="Personal tools" > <label id="vector-user-links-dropdown-label" for="vector-user-links-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-ellipsis mw-ui-icon-wikimedia-ellipsis"></span> <span class="vector-dropdown-label-text">Personal tools</span> </label> <div class="vector-dropdown-content"> <div id="p-personal" class="vector-menu mw-portlet mw-portlet-personal user-links-collapsible-item" title="User menu" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport" class="user-links-collapsible-item mw-list-item"><a href="//donate.wikimedia.org/wiki/Special:FundraiserRedirector?utm_source=donate&utm_medium=sidebar&utm_campaign=C13_en.wikibooks.org&uselang=en"><span>Donations</span></a></li><li id="pt-createaccount" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:CreateAccount&returnto=JavaScript" title="You are encouraged to create an account and log in; however, it is not mandatory"><span class="vector-icon mw-ui-icon-userAdd mw-ui-icon-wikimedia-userAdd"></span> <span>Create account</span></a></li><li id="pt-login" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:UserLogin&returnto=JavaScript" title="You are encouraged to log in; however, it is not mandatory [o]" accesskey="o"><span class="vector-icon mw-ui-icon-logIn mw-ui-icon-wikimedia-logIn"></span> <span>Log in</span></a></li> </ul> </div> </div> <div id="p-user-menu-anon-editor" class="vector-menu mw-portlet mw-portlet-user-menu-anon-editor" > <div class="vector-menu-heading"> Pages for logged out editors <a href="/wiki/Help:Introduction" aria-label="Learn more about editing"><span>learn more</span></a> </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-anoncontribs" class="mw-list-item"><a href="/wiki/Special:MyContributions" title="A list of edits made from this IP address [y]" accesskey="y"><span>Contributions</span></a></li><li id="pt-anontalk" class="mw-list-item"><a href="/wiki/Special:MyTalk" title="Discussion about edits from this IP address [n]" accesskey="n"><span>Discussion for this IP address</span></a></li> </ul> </div> </div> </div> </div> </nav> </div> </header> </div> <div class="mw-page-container"> <div class="mw-page-container-inner"> <div class="vector-sitenotice-container"> <div id="siteNotice"><div id="mw-dismissablenotice-anonplace"></div><script>(function(){var node=document.getElementById("mw-dismissablenotice-anonplace");if(node){node.outerHTML="\u003Cdiv class=\"mw-dismissable-notice\"\u003E\u003Cdiv class=\"mw-dismissable-notice-close\"\u003E[\u003Ca tabindex=\"0\" role=\"button\"\u003Edismiss\u003C/a\u003E]\u003C/div\u003E\u003Cdiv class=\"mw-dismissable-notice-body\"\u003E\u003C!-- CentralNotice --\u003E\u003Cdiv id=\"localNotice\" data-nosnippet=\"\"\u003E\u003Cdiv class=\"anonnotice\" lang=\"en\" dir=\"ltr\"\u003E\u003Cdiv style=\"width: fit-content; padding: 5px; border: 3px solid gray; background-color: #fafafa; text-align: center; margin: auto;\"\u003E\n\u003Cp\u003E\u003Cspan typeof=\"mw:File\"\u003E\u003Ca href=\"/wiki/File:OOjs_UI_icon_robot.svg\" class=\"mw-file-description\"\u003E\u003Cimg src=\"//upload.wikimedia.org/wikipedia/commons/thumb/7/71/OOjs_UI_icon_robot.svg/40px-OOjs_UI_icon_robot.svg.png\" decoding=\"async\" width=\"40\" height=\"40\" class=\"mw-file-element\" srcset=\"//upload.wikimedia.org/wikipedia/commons/thumb/7/71/OOjs_UI_icon_robot.svg/60px-OOjs_UI_icon_robot.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/7/71/OOjs_UI_icon_robot.svg/80px-OOjs_UI_icon_robot.svg.png 2x\" data-file-width=\"20\" data-file-height=\"20\" /\u003E\u003C/a\u003E\u003C/span\u003E The Wikibooks community is developing a policy on the use of generative AI. Please review the \u003Ca href=\"/wiki/Wikibooks:Artificial_Intelligence\" title=\"Wikibooks:Artificial Intelligence\"\u003Edraft policy\u003C/a\u003E and provide feedback on \u003Ca href=\"/wiki/Wikibooks_talk:Artificial_Intelligence\" title=\"Wikibooks talk:Artificial Intelligence\"\u003Eits talk page\u003C/a\u003E.\n\u003C/p\u003E\n\u003C/div\u003E\u003C/div\u003E\u003C/div\u003E\u003C/div\u003E\u003C/div\u003E";}}());</script></div> </div> <div class="vector-column-start"> <div class="vector-main-menu-container"> <div id="mw-navigation"> <nav id="mw-panel" class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-pinned-container" class="vector-pinned-container"> </div> </nav> </div> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <h1 id="firstHeading" class="firstHeading mw-first-heading"><span class="mw-page-title-main">JavaScript</span></h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet mw-portlet-lang" > <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Go to an article in another language. Available in 27 languages" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-27" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">27 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikibooks.org/wiki/%D8%A8%D8%B1%D9%85%D8%AC%D8%A9_%D8%AC%D8%A7%D9%81%D8%A7_%D8%B3%D9%83%D8%B1%D9%8A%D8%A8%D8%AA" title="برمجة جافا سكريبت – Arabic" lang="ar" hreflang="ar" data-title="برمجة جافا سكريبت" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-az mw-list-item"><a href="https://az.wikibooks.org/wiki/JavaScript" title="JavaScript – Azerbaijani" lang="az" hreflang="az" data-title="JavaScript" data-language-autonym="Azərbaycanca" data-language-local-name="Azerbaijani" class="interlanguage-link-target"><span>Azərbaycanca</span></a></li><li class="interlanguage-link interwiki-bg mw-list-item"><a href="https://bg.wikibooks.org/wiki/JavaScript" title="JavaScript – Bulgarian" lang="bg" hreflang="bg" data-title="JavaScript" data-language-autonym="Български" data-language-local-name="Bulgarian" class="interlanguage-link-target"><span>Български</span></a></li><li class="interlanguage-link interwiki-bn mw-list-item"><a href="https://bn.wikibooks.org/wiki/%E0%A6%9C%E0%A6%BE%E0%A6%AD%E0%A6%BE%E0%A6%B8%E0%A7%8D%E0%A6%95%E0%A7%8D%E0%A6%B0%E0%A6%BF%E0%A6%AA%E0%A7%8D%E0%A6%9F" title="জাভাস্ক্রিপ্ট – Bangla" lang="bn" hreflang="bn" data-title="জাভাস্ক্রিপ্ট" data-language-autonym="বাংলা" data-language-local-name="Bangla" class="interlanguage-link-target"><span>বাংলা</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikibooks.org/wiki/Websiteentwicklung:_JavaScript" title="Websiteentwicklung: JavaScript – German" lang="de" hreflang="de" data-title="Websiteentwicklung: JavaScript" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikibooks.org/wiki/Programaci%C3%B3n_en_JavaScript" title="Programación en JavaScript – Spanish" lang="es" hreflang="es" data-title="Programación en JavaScript" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikibooks.org/wiki/%D8%AC%D8%A7%D9%88%D8%A7_%D8%A7%D8%B3%DA%A9%D8%B1%DB%8C%D9%BE%D8%AA" title="جاوا اسکریپت – Persian" lang="fa" hreflang="fa" data-title="جاوا اسکریپت" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-fi mw-list-item"><a href="https://fi.wikibooks.org/wiki/JavaScript" title="JavaScript – Finnish" lang="fi" hreflang="fi" data-title="JavaScript" data-language-autonym="Suomi" data-language-local-name="Finnish" class="interlanguage-link-target"><span>Suomi</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikibooks.org/wiki/Programmation_JavaScript" title="Programmation JavaScript – French" lang="fr" hreflang="fr" data-title="Programmation JavaScript" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-gl mw-list-item"><a href="https://gl.wikibooks.org/wiki/JavaScript" title="JavaScript – Galician" lang="gl" hreflang="gl" data-title="JavaScript" data-language-autonym="Galego" data-language-local-name="Galician" class="interlanguage-link-target"><span>Galego</span></a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikibooks.org/wiki/JavaScript" title="JavaScript – Hebrew" lang="he" hreflang="he" data-title="JavaScript" data-language-autonym="עברית" data-language-local-name="Hebrew" class="interlanguage-link-target"><span>עברית</span></a></li><li class="interlanguage-link interwiki-hu mw-list-item"><a href="https://hu.wikibooks.org/wiki/Java_Script" title="Java Script – Hungarian" lang="hu" hreflang="hu" data-title="Java Script" data-language-autonym="Magyar" data-language-local-name="Hungarian" class="interlanguage-link-target"><span>Magyar</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikibooks.org/wiki/JavaScript" title="JavaScript – Indonesian" lang="id" hreflang="id" data-title="JavaScript" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-is mw-list-item"><a href="https://is.wikibooks.org/wiki/JavaScript" title="JavaScript – Icelandic" lang="is" hreflang="is" data-title="JavaScript" data-language-autonym="Íslenska" data-language-local-name="Icelandic" class="interlanguage-link-target"><span>Íslenska</span></a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikibooks.org/wiki/JavaScript" title="JavaScript – Italian" lang="it" hreflang="it" data-title="JavaScript" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikibooks.org/wiki/JavaScript" title="JavaScript – Japanese" lang="ja" hreflang="ja" data-title="JavaScript" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-ms mw-list-item"><a href="https://ms.wikibooks.org/wiki/JavaScript" title="JavaScript – Malay" lang="ms" hreflang="ms" data-title="JavaScript" data-language-autonym="Bahasa Melayu" data-language-local-name="Malay" class="interlanguage-link-target"><span>Bahasa Melayu</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikibooks.org/wiki/Programmeren_in_JavaScript" title="Programmeren in JavaScript – Dutch" lang="nl" hreflang="nl" data-title="Programmeren in JavaScript" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikibooks.org/wiki/JavaScript" title="JavaScript – Polish" lang="pl" hreflang="pl" data-title="JavaScript" data-language-autonym="Polski" data-language-local-name="Polish" class="interlanguage-link-target"><span>Polski</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikibooks.org/wiki/Javascript" title="Javascript – Portuguese" lang="pt" hreflang="pt" data-title="Javascript" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikibooks.org/wiki/%D0%9A%D0%BD%D0%B8%D0%B3%D0%B0_JavaScript" title="Книга JavaScript – Russian" lang="ru" hreflang="ru" data-title="Книга JavaScript" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-sq mw-list-item"><a href="https://sq.wikibooks.org/wiki/Java_Scripts_Libri" title="Java Scripts Libri – Albanian" lang="sq" hreflang="sq" data-title="Java Scripts Libri" data-language-autonym="Shqip" data-language-local-name="Albanian" class="interlanguage-link-target"><span>Shqip</span></a></li><li class="interlanguage-link interwiki-ta mw-list-item"><a href="https://ta.wikibooks.org/wiki/%E0%AE%AF%E0%AE%BE%E0%AE%B5%E0%AE%BE%E0%AE%95%E0%AF%8D%E0%AE%95%E0%AE%BF%E0%AE%B1%E0%AE%BF%E0%AE%9F%E0%AF%8D%E0%AE%9F%E0%AF%81" title="யாவாக்கிறிட்டு – Tamil" lang="ta" hreflang="ta" data-title="யாவாக்கிறிட்டு" data-language-autonym="தமிழ்" data-language-local-name="Tamil" class="interlanguage-link-target"><span>தமிழ்</span></a></li><li class="interlanguage-link interwiki-th mw-list-item"><a href="https://th.wikibooks.org/wiki/%E0%B8%88%E0%B8%B2%E0%B8%A7%E0%B8%B2%E0%B8%AA%E0%B8%84%E0%B8%A3%E0%B8%B4%E0%B8%9B%E0%B8%95%E0%B9%8C" title="จาวาสคริปต์ – Thai" lang="th" hreflang="th" data-title="จาวาสคริปต์" data-language-autonym="ไทย" data-language-local-name="Thai" class="interlanguage-link-target"><span>ไทย</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikibooks.org/wiki/JavaScript" title="JavaScript – Turkish" lang="tr" hreflang="tr" data-title="JavaScript" data-language-autonym="Türkçe" data-language-local-name="Turkish" class="interlanguage-link-target"><span>Türkçe</span></a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikibooks.org/wiki/JavaScript" title="JavaScript – Vietnamese" lang="vi" hreflang="vi" data-title="JavaScript" data-language-autonym="Tiếng Việt" data-language-local-name="Vietnamese" class="interlanguage-link-target"><span>Tiếng Việt</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikibooks.org/wiki/JavaScript" title="JavaScript – Chinese" lang="zh" hreflang="zh" data-title="JavaScript" data-language-autonym="中文" data-language-local-name="Chinese" class="interlanguage-link-target"><span>中文</span></a></li> </ul> <div class="after-portlet after-portlet-lang"><span class="wb-langlinks-edit wb-langlinks-link"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q2005#sitelinks-wikibooks" title="Edit interlanguage links" class="wbc-editpage">Edit links</a></span></div> </div> </div> </div> </header> <div class="vector-page-toolbar"> <div class="vector-page-toolbar-container"> <div id="left-navigation"> <nav aria-label="Namespaces"> <div id="p-associated-pages" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-associated-pages" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-nstab-main" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/JavaScript" title="View the content page [c]" accesskey="c"><span>Book</span></a></li><li id="ca-talk" class="vector-tab-noicon mw-list-item"><a href="/wiki/Talk:JavaScript" rel="discussion" title="Discussion about the content page [t]" accesskey="t"><span>Discussion</span></a></li> </ul> </div> </div> <div id="vector-variants-dropdown" class="vector-dropdown emptyPortlet" > <input type="checkbox" id="vector-variants-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-variants-dropdown" class="vector-dropdown-checkbox " aria-label="Change language variant" > <label id="vector-variants-dropdown-label" for="vector-variants-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" ><span class="vector-dropdown-label-text">English</span> </label> <div class="vector-dropdown-content"> <div id="p-variants" class="vector-menu mw-portlet mw-portlet-variants emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> </div> </div> </nav> </div> <div id="right-navigation" class="vector-collapsible"> <nav aria-label="Views"> <div id="p-views" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-views" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-view" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/JavaScript"><span>Read</span></a></li><li id="ca-ve-edit" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=JavaScript&veaction=edit" title="Edit this page [v]" accesskey="v"><span>Edit</span></a></li><li id="ca-edit" class="collapsible vector-tab-noicon mw-list-item"><a href="/w/index.php?title=JavaScript&action=edit" title="Edit the source code of this page [e]" accesskey="e"><span>Edit source</span></a></li><li id="ca-history" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=JavaScript&action=history" title="Past revisions of this page [h]" accesskey="h"><span>View history</span></a></li> </ul> </div> </div> </nav> <nav class="vector-page-tools-landmark" aria-label="Page tools"> <div id="vector-page-tools-dropdown" class="vector-dropdown vector-page-tools-dropdown" > <input type="checkbox" id="vector-page-tools-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-tools-dropdown" class="vector-dropdown-checkbox " aria-label="Tools" > <label id="vector-page-tools-dropdown-label" for="vector-page-tools-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" ><span class="vector-dropdown-label-text">Tools</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-tools-unpinned-container" class="vector-unpinned-container"> <div id="vector-page-tools" class="vector-page-tools vector-pinnable-element"> <div class="vector-pinnable-header vector-page-tools-pinnable-header vector-pinnable-header-unpinned" data-feature-name="page-tools-pinned" data-pinnable-element-id="vector-page-tools" data-pinned-container-id="vector-page-tools-pinned-container" data-unpinned-container-id="vector-page-tools-unpinned-container" > <div class="vector-pinnable-header-label">Tools</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-page-tools.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-page-tools.unpin">hide</button> </div> <div id="p-cactions" class="vector-menu mw-portlet mw-portlet-cactions emptyPortlet vector-has-collapsible-items" title="More options" > <div class="vector-menu-heading"> Actions </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-more-view" class="selected vector-more-collapsible-item mw-list-item"><a href="/wiki/JavaScript"><span>Read</span></a></li><li id="ca-more-ve-edit" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=JavaScript&veaction=edit" title="Edit this page [v]" accesskey="v"><span>Edit</span></a></li><li id="ca-more-edit" class="collapsible vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=JavaScript&action=edit" title="Edit the source code of this page [e]" accesskey="e"><span>Edit source</span></a></li><li id="ca-more-history" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=JavaScript&action=history"><span>View history</span></a></li> </ul> </div> </div> <div id="p-tb" class="vector-menu mw-portlet mw-portlet-tb" > <div class="vector-menu-heading"> General </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="t-whatlinkshere" class="mw-list-item"><a href="/wiki/Special:WhatLinksHere/JavaScript" title="A list of all wiki pages that link here [j]" accesskey="j"><span>What links here</span></a></li><li id="t-recentchangeslinked" class="mw-list-item"><a href="/wiki/Special:RecentChangesLinked/JavaScript" rel="nofollow" title="Recent changes in pages linked from this page [k]" accesskey="k"><span>Related changes</span></a></li><li id="t-upload" class="mw-list-item"><a href="//commons.wikimedia.org/wiki/Special:UploadWizard?uselang=en" title="Upload files [u]" accesskey="u"><span>Upload file</span></a></li><li id="t-specialpages" class="mw-list-item"><a href="/wiki/Special:SpecialPages" title="A list of all special pages [q]" accesskey="q"><span>Special pages</span></a></li><li id="t-permalink" class="mw-list-item"><a href="/w/index.php?title=JavaScript&oldid=4416493" title="Permanent link to this revision of this page"><span>Permanent link</span></a></li><li id="t-info" class="mw-list-item"><a href="/w/index.php?title=JavaScript&action=info" title="More information about this page"><span>Page information</span></a></li><li id="t-cite" class="mw-list-item"><a href="/w/index.php?title=Special:CiteThisPage&page=JavaScript&id=4416493&wpFormIdentifier=titleform" title="Information on how to cite this page"><span>Cite this page</span></a></li><li id="t-urlshortener" class="mw-list-item"><a href="/w/index.php?title=Special:UrlShortener&url=https%3A%2F%2Fen.wikibooks.org%2Fwiki%2FJavaScript"><span>Get shortened URL</span></a></li><li id="t-urlshortener-qrcode" class="mw-list-item"><a href="/w/index.php?title=Special:QrCode&url=https%3A%2F%2Fen.wikibooks.org%2Fwiki%2FJavaScript"><span>Download QR code</span></a></li> </ul> </div> </div> <div id="p-sister_projects" class="vector-menu mw-portlet mw-portlet-sister_projects" > <div class="vector-menu-heading"> Sister projects </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-Wikipedia" class="mw-list-item"><a href="https://en.wikipedia.org/wiki/Main_Page"><span>Wikipedia</span></a></li><li id="n-Wikiversity" class="mw-list-item"><a href="https://en.wikiversity.org/wiki/Wikiversity:Main_Page"><span>Wikiversity</span></a></li><li id="n-Wiktionary" class="mw-list-item"><a href="https://en.wiktionary.org/wiki/Wiktionary:Main_Page"><span>Wiktionary</span></a></li><li id="n-Wikiquote" class="mw-list-item"><a href="https://en.wikiquote.org/wiki/Main_Page"><span>Wikiquote</span></a></li><li id="n-Wikisource" class="mw-list-item"><a href="https://en.wikisource.org/wiki/Main_Page"><span>Wikisource</span></a></li><li id="n-Wikinews" class="mw-list-item"><a href="https://en.wikinews.org/wiki/Main_Page"><span>Wikinews</span></a></li><li id="n-Wikivoyage" class="mw-list-item"><a href="https://en.wikivoyage.org/wiki/Main_Page"><span>Wikivoyage</span></a></li><li id="n-Commons" class="mw-list-item"><a href="https://commons.wikimedia.org/wiki/Main_Page"><span>Commons</span></a></li><li id="n-Wikidata" class="mw-list-item"><a href="https://www.wikidata.org/wiki/Wikidata:Main_Page"><span>Wikidata</span></a></li><li id="n-MediaWiki" class="mw-list-item"><a href="https://www.mediawiki.org/wiki/Main_Page"><span>MediaWiki</span></a></li><li id="n-Meta-Wiki" class="mw-list-item"><a href="https://meta.wikimedia.org/wiki/Main_Page"><span>Meta-Wiki</span></a></li> </ul> </div> </div> <div id="p-coll-print_export" class="vector-menu mw-portlet mw-portlet-coll-print_export" > <div class="vector-menu-heading"> Print/export </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="coll-create_a_book" class="mw-list-item"><a href="/w/index.php?title=Special:Book&bookcmd=book_creator&referer=JavaScript"><span>Create a collection</span></a></li><li id="coll-download-as-rl" class="mw-list-item"><a href="/w/index.php?title=Special:DownloadAsPdf&page=JavaScript&action=show-download-screen"><span>Download as PDF</span></a></li><li id="t-print" class="mw-list-item"><a href="/w/index.php?title=JavaScript&printable=yes" title="Printable version of this page [p]" accesskey="p"><span>Printable version</span></a></li> </ul> </div> </div> <div id="p-wikibase-otherprojects" class="vector-menu mw-portlet mw-portlet-wikibase-otherprojects" > <div class="vector-menu-heading"> In other projects </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="wb-otherproject-link wb-otherproject-commons mw-list-item"><a href="https://commons.wikimedia.org/wiki/Category:JavaScript" hreflang="en"><span>Wikimedia Commons</span></a></li><li class="wb-otherproject-link wb-otherproject-mediawiki mw-list-item"><a href="https://www.mediawiki.org/wiki/JavaScript" hreflang="en"><span>MediaWiki</span></a></li><li class="wb-otherproject-link wb-otherproject-wikifunctions mw-list-item"><a href="https://www.wikifunctions.org/wiki/Z600" hreflang="en"><span>Wikifunctions</span></a></li><li class="wb-otherproject-link wb-otherproject-wikipedia mw-list-item"><a href="https://en.wikipedia.org/wiki/JavaScript" hreflang="en"><span>Wikipedia</span></a></li><li class="wb-otherproject-link wb-otherproject-wikiversity mw-list-item"><a href="https://en.wikiversity.org/wiki/JavaScript_Programming" hreflang="en"><span>Wikiversity</span></a></li><li id="t-wikibase" class="wb-otherproject-link wb-otherproject-wikibase-dataitem mw-list-item"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q2005" title="Link to connected data repository item [g]" accesskey="g"><span>Wikidata item</span></a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> </div> </div> </div> <div class="vector-column-end"> <div class="vector-sticky-pinned-container"> <nav class="vector-page-tools-landmark" aria-label="Page tools"> <div id="vector-page-tools-pinned-container" class="vector-pinned-container"> </div> </nav> <nav class="vector-appearance-landmark" aria-label="Appearance"> <div id="vector-appearance-pinned-container" class="vector-pinned-container"> <div id="vector-appearance" class="vector-appearance vector-pinnable-element"> <div class="vector-pinnable-header vector-appearance-pinnable-header vector-pinnable-header-pinned" data-feature-name="appearance-pinned" data-pinnable-element-id="vector-appearance" data-pinned-container-id="vector-appearance-pinned-container" data-unpinned-container-id="vector-appearance-unpinned-container" > <div class="vector-pinnable-header-label">Appearance</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-appearance.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-appearance.unpin">hide</button> </div> </div> </div> </nav> </div> </div> <div id="bodyContent" class="vector-body" aria-labelledby="firstHeading" data-mw-ve-target-container> <div class="vector-body-before-content"> <div class="mw-indicators"> <div id="mw-indicator-status-icon" class="mw-indicator"><div class="mw-parser-output"><span typeof="mw:File"><a href="/wiki/Help:Development_stages" title="50% developed"><img alt="50% developed" src="//upload.wikimedia.org/wikipedia/commons/thumb/6/62/50_percents.svg/24px-50_percents.svg.png" decoding="async" width="24" height="24" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/62/50_percents.svg/36px-50_percents.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/62/50_percents.svg/48px-50_percents.svg.png 2x" data-file-width="9" data-file-height="9" /></a></span></div></div> </div> <div id="siteSub" class="noprint">From Wikibooks, open books for an open world</div> </div> <div id="contentSub"><div id="mw-content-subtitle"></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><div style="text-align:center;"> <div style="font-size:x-large;">JavaScript</div> <div style="margin-top:5px;"><i>Scripting for the web.</i></div> </div> <p>This book is a guide to JavaScript, a scripting language widely used in web pages and web applications such as email applications. JavaScript is not to be confused with <a href="/wiki/Java" class="mw-redirect" title="Java">Java</a>, which is quite a separate language for creating stand-alone applications. </p><p><i>This book applies to version 1.6 and later of JavaScript. Multiple versions of JavaScript are covered in this book.</i> </p> <div class="mw-heading mw-heading2"><h2 id="Welcome">Welcome</h2></div> <div class="noprint" style="float:right; clear:right; margin:0 0 1em 1em; width:250px;"> <table> <tbody><tr> <td style="width:50px;"> </td> <td style="width:385px;"> <div class="mw-inputbox-centered" style=""><form name="searchbox" class="searchbox mw-inputbox-form" action="/wiki/Special:Search"><div class="cdx-text-input"><input class="mw-inputbox-input mw-searchInput searchboxInput cdx-text-input__input" name="search" placeholder="" size="13" dir="ltr" /></div><input type="hidden" value="JavaScript/" name="prefix" /><br /><input type="submit" name="fulltext" value="Search this book" class="cdx-button" /><input type="hidden" value="Search" name="fulltext" /></form></div> </td></tr></tbody></table> </div> <table class="plainlinks noprint messagebox growth" style="width:250px; float:right; clear:right; margin:0px; margin-left:10px;"> <tbody><tr style="vertical-align:middle;"><td style="padding:0.1em; text-align:center; vertical-align:middle; width:45px; border:none;"> <span typeof="mw:File"><span><img src="//upload.wikimedia.org/wikipedia/commons/thumb/2/23/Printer.svg/40px-Printer.svg.png" decoding="async" width="40" height="40" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/23/Printer.svg/60px-Printer.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/23/Printer.svg/80px-Printer.svg.png 2x" data-file-width="48" data-file-height="48" /></span></span></td> <td style="color:black; text-align:left; vertical-align:middle; padding:0.5em; padding-left:0em; border:none;"> <p>A <i><b><a href="/wiki/JavaScript/Print_version" title="JavaScript/Print version">printable version</a></b></i> of JavaScript is available. <small> (<a class="external text" href="https://en.wikibooks.org/w/index.php?title=JavaScript/Print_version&action=edit&preload=Template%3APrint+version%2FPreload">edit it</a>)</small> </p> </td></tr></tbody></table> <table class="plainlinks noprint messagebox growth" style="width:250px; float:right; clear:right; margin:0px; margin-left:10px;"> <tbody><tr style="vertical-align:middle;"><td style="padding:0.1em; text-align:center; vertical-align:middle; width:45px; border:none;"> <span typeof="mw:File"><span><img src="//upload.wikimedia.org/wikipedia/commons/thumb/b/b6/Gnome-mime-application-pdf.svg/40px-Gnome-mime-application-pdf.svg.png" decoding="async" width="40" height="40" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/b/b6/Gnome-mime-application-pdf.svg/60px-Gnome-mime-application-pdf.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/b/b6/Gnome-mime-application-pdf.svg/80px-Gnome-mime-application-pdf.svg.png 2x" data-file-width="64" data-file-height="64" /></span></span></td> <td style="color:black; text-align:left; vertical-align:middle; padding:0.5em; padding-left:0em; border:none;"> <p>A <i><b><a href="//upload.wikimedia.org/wikipedia/commons/d/d0/JavaScript.pdf" class="internal" title="JavaScript.pdf">PDF version</a></b></i> is available. <small> (<a href="/wiki/File:JavaScript.pdf" title="File:JavaScript.pdf">info</a>) </small> </p> </td></tr></tbody></table> <ul><li><a href="/wiki/JavaScript/Introduction" title="JavaScript/Introduction">Introduction</a> (<a href="/wiki/JavaScript/Relation_to_other_languages" title="JavaScript/Relation to other languages">Relation to other languages</a>)</li> <li><a href="/wiki/JavaScript/First_program" title="JavaScript/First program">Hello World!</a></li> <li><a href="/wiki/JavaScript/Placing_the_code" class="mw-redirect" title="JavaScript/Placing the code">Placing the code</a></li> <li><a href="/wiki/JavaScript/Other_Script_Types" title="JavaScript/Other Script Types">Other Script Types</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="Core_Language">Core Language</h2></div> <ul><li><a href="/wiki/JavaScript/Lexical_structure" title="JavaScript/Lexical structure">Lexical structure</a> <ul><li><a href="/wiki/JavaScript/Automatic_semicolon_insertion" title="JavaScript/Automatic semicolon insertion">Automatic semicolon insertion (ASI)</a></li> <li><a href="/wiki/JavaScript/Reserved_words" title="JavaScript/Reserved words">Reserved words</a></li></ul></li> <li><a href="/wiki/JavaScript/Variables_and_types" class="mw-redirect" title="JavaScript/Variables and types">Variables and types</a> <ul><li><a href="/wiki/JavaScript/Numbers" class="mw-redirect" title="JavaScript/Numbers">Numbers</a></li> <li><a href="/wiki/JavaScript/Strings" class="mw-redirect" title="JavaScript/Strings">Strings</a></li> <li><a href="/wiki/JavaScript/Dates" title="JavaScript/Dates">Dates</a></li> <li><a href="/wiki/JavaScript/Arrays" title="JavaScript/Arrays">Arrays</a></li> <li><a href="/wiki/JavaScript/Regular_expressions" title="JavaScript/Regular expressions">Regular expressions</a></li></ul></li> <li><a href="/wiki/JavaScript/Operators" title="JavaScript/Operators">Operators</a></li> <li><a href="/wiki/JavaScript/Control_structures" title="JavaScript/Control structures">Program flow I: if, switch, try</a></li> <li><a href="/wiki/JavaScript/Loops" title="JavaScript/Loops">Program flow II: loops</a></li> <li><a href="/wiki/JavaScript/Functions" title="JavaScript/Functions">Functions</a> <ul><li><a href="/wiki/JavaScript/Anonymous_functions" class="mw-redirect" title="JavaScript/Anonymous functions">Anonymous functions</a></li></ul></li> <li><a href="/wiki/JavaScript/Object-based_programming" title="JavaScript/Object-based programming">Object-based programming</a> <ul><li><a href="/wiki/JavaScript/Objects" title="JavaScript/Objects">Objects</a></li> <li><a href="/wiki/JavaScript/Constructors_and_prototypes" title="JavaScript/Constructors and prototypes">Constructors and prototypes</a></li> <li><a href="/wiki/JavaScript/Inheritance" title="JavaScript/Inheritance">Inheritance</a></li> <li><a href="/wiki/JavaScript/Access_control" title="JavaScript/Access control">Access control</a></li></ul></li> <li><a href="/wiki/JavaScript/Closures" title="JavaScript/Closures">Closures</a></li> <li><a href="/wiki/JavaScript/Debugging" title="JavaScript/Debugging">Debugging</a></li> <li><a href="/wiki/JavaScript/Optimization" title="JavaScript/Optimization">Optimization</a></li> <li><a href="/wiki/JavaScript/Strict_Mode" class="mw-redirect" title="JavaScript/Strict Mode">Strict Mode</a></li> <li><a href="/wiki/JavaScript/Shell" title="JavaScript/Shell">Shell</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="Document_Object_Model_and_Dynamic_Websites"><a href="/wiki/JavaScript/Introduction_to_the_Document_Object_Model_(DOM)" title="JavaScript/Introduction to the Document Object Model (DOM)">Document Object Model</a> and <a href="/wiki/JavaScript/DHTML" title="JavaScript/DHTML">Dynamic Websites</a></h2></div> <ul><li><a href="/wiki/JavaScript/Runtime_document_manipulation" class="mw-redirect" title="JavaScript/Runtime document manipulation">Runtime document manipulation</a> <ul><li><a href="/wiki/JavaScript/Finding_elements" title="JavaScript/Finding elements">Finding elements</a></li> <li><a href="/wiki/JavaScript/Adding_elements" title="JavaScript/Adding elements">Adding elements</a></li> <li><a href="/wiki/JavaScript/Changing_elements" title="JavaScript/Changing elements">Changing elements</a></li> <li><a href="/wiki/JavaScript/Removing_elements" title="JavaScript/Removing elements">Removing elements</a></li> <li><a href="/wiki/JavaScript/Changing_element_styles" title="JavaScript/Changing element styles">Changing element styles</a></li></ul></li> <li><a href="/wiki/JavaScript/Event_handling" class="mw-redirect" title="JavaScript/Event handling">Event handling</a></li> <li><a href="/wiki/JavaScript/W3C_event_handlers" title="JavaScript/W3C event handlers">W3C event handlers</a></li> <li><a href="/wiki/JavaScript/Working_with_the_mouse" title="JavaScript/Working with the mouse">Working with the mouse</a></li> <li><a href="/wiki/JavaScript/Forms" title="JavaScript/Forms">Forms</a></li> <li><a href="/wiki/JavaScript/Images" title="JavaScript/Images">Images</a></li> <li><a href="/wiki/JavaScript/Cookies" title="JavaScript/Cookies">Cookies</a></li> <li><a href="/wiki/JavaScript/LocalStorage" title="JavaScript/LocalStorage">LocalStorage</a></li> <li><a href="/w/index.php?title=JavaScript/Design_Mode&action=edit&redlink=1" class="new" title="JavaScript/Design Mode (does not exist)">Design Mode</a></li> <li><a href="/wiki/JavaScript/Bookmarklets" title="JavaScript/Bookmarklets">Bookmarklets</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="Client-Server_Programming_with_AJAX">Client-Server Programming with AJAX</h2></div> <ul><li><a href="/wiki/JavaScript/XMLHttpRequest" title="JavaScript/XMLHttpRequest">XMLHttpRequest</a></li> <li><a href="/wiki/JavaScript/Handling_HTML" title="JavaScript/Handling HTML">Handling HTML</a></li> <li><a href="/wiki/JavaScript/Handling_JSON" title="JavaScript/Handling JSON">Handling JSON</a></li> <li><a href="/wiki/JavaScript/Handling_XML" title="JavaScript/Handling XML">Handling XML</a></li> <li><a href="/wiki/JavaScript/Working_with_files" title="JavaScript/Working with files">Working with files</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="Miscellaneous">Miscellaneous</h2></div> <ul><li><a href="/wiki/JavaScript/JScript_in_Microsoft_WSH" title="JavaScript/JScript in Microsoft WSH">JScript in Microsoft WSH</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="Appendices">Appendices</h2></div> <ul><li><a href="/wiki/JavaScript/Index" title="JavaScript/Index">Index</a></li> <li><a href="/wiki/JavaScript/Links" title="JavaScript/Links">Links</a></li> <li><a href="/wiki/JavaScript/Bookmarklets" title="JavaScript/Bookmarklets">Bookmarklets</a></li> <li><a href="/wiki/JavaScript/Useful_software_tools" title="JavaScript/Useful software tools">Useful software tools</a></li> <li><a href="/wiki/JavaScript/History_of_JavaScript" title="JavaScript/History of JavaScript">History of JavaScript</a></li> <li><a href="/wiki/JavaScript/Best_practices" title="JavaScript/Best practices">Best practices</a></li> <li><a href="/wiki/JavaScript/Code_structuring" title="JavaScript/Code structuring">Code structuring</a></li> <li><a href="/wiki/JavaScript/Generators" title="JavaScript/Generators">Generators</a></li> <li><a href="/wiki/JavaScript/Contributors" title="JavaScript/Contributors">Contributors</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="Related_books">Related books</h2></div> <ul><li><a href="/wiki/ActionScript_Programming" title="ActionScript Programming">ActionScript Programming</a></li> <li><a href="/wiki/Authoring_Webpages" title="Authoring Webpages">Authoring Webpages</a></li> <li><a href="/wiki/Cascading_Style_Sheets" title="Cascading Style Sheets">Cascading Style Sheets</a></li> <li><a href="/wiki/Category:CodeCook/Languages/JavaScript" title="Category:CodeCook/Languages/JavaScript">Coding Cookbook: JavaScript</a></li> <li><a href="/wiki/HyperText_Markup_Language" title="HyperText Markup Language">HyperText Markup Language</a></li> <li><a href="/wiki/Programming_Ajax" title="Programming Ajax">Programming Ajax</a></li> <li><a href="/wiki/Web_Development" title="Web Development">Web Development</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="Wikimedia">Wikimedia</h2></div> <ul><li><a href="https://en.wikipedia.org/wiki/JavaScript" class="extiw" title="w:JavaScript">JavaScript in Wikipedia</a></li> <li><a href="https://en.wikiversity.org/wiki/Web_Design/An_Introduction_to_Programming_with_JavaScript" class="extiw" title="wikiversity:Web Design/An Introduction to Programming with JavaScript">Wikiversity:Web Design/An Introduction to Programming with JavaScript</a></li></ul></div><noscript><img src="https://login.wikimedia.org/wiki/Special:CentralAutoLogin/start?type=1x1" alt="" width="1" height="1" style="border: none; position: absolute;"></noscript> <div class="printfooter" data-nosnippet="">Retrieved from "<a dir="ltr" href="https://en.wikibooks.org/w/index.php?title=JavaScript&oldid=4416493">https://en.wikibooks.org/w/index.php?title=JavaScript&oldid=4416493</a>"</div></div> <div id="catlinks" class="catlinks" data-mw="interface"><div id="mw-normal-catlinks" class="mw-normal-catlinks"><a href="/wiki/Special:Categories" title="Special:Categories">Categories</a>: <ul><li><a href="/wiki/Category:Book:JavaScript" title="Category:Book:JavaScript">Book:JavaScript</a></li><li><a href="/wiki/Category:Shelf:JavaScript_scripting_language" title="Category:Shelf:JavaScript scripting language">Shelf:JavaScript scripting language</a></li></ul></div><div id="mw-hidden-catlinks" class="mw-hidden-catlinks mw-hidden-cats-hidden">Hidden categories: <ul><li><a href="/wiki/Category:Books_with_print_version" title="Category:Books with print version">Books with print version</a></li><li><a href="/wiki/Category:Books_with_PDF_version" title="Category:Books with PDF version">Books with PDF version</a></li><li><a href="/wiki/Category:Subject:JavaScript_scripting_language" title="Category:Subject:JavaScript scripting language">Subject:JavaScript scripting language</a></li><li><a href="/wiki/Category:Subject:JavaScript_scripting_language/all_books" title="Category:Subject:JavaScript scripting language/all books">Subject:JavaScript scripting language/all books</a></li><li><a href="/wiki/Category:Subject:Scripting_languages/all_books" title="Category:Subject:Scripting languages/all books">Subject:Scripting languages/all books</a></li><li><a href="/wiki/Category:Subject:Computer_programming_languages/all_books" title="Category:Subject:Computer programming languages/all books">Subject:Computer programming languages/all books</a></li><li><a href="/wiki/Category:Subject:Computer_programming/all_books" title="Category:Subject:Computer programming/all books">Subject:Computer programming/all books</a></li><li><a href="/wiki/Category:Subject:Computer_science/all_books" title="Category:Subject:Computer science/all books">Subject:Computer science/all books</a></li><li><a href="/wiki/Category:Subject:Computing/all_books" title="Category:Subject:Computing/all books">Subject:Computing/all books</a></li><li><a href="/wiki/Category:Subject:Books_by_subject/all_books" title="Category:Subject:Books by subject/all books">Subject:Books by subject/all books</a></li><li><a href="/wiki/Category:Subject:Web_development/all_books" title="Category:Subject:Web development/all books">Subject:Web development/all books</a></li><li><a href="/wiki/Category:Subject:Internet/all_books" title="Category:Subject:Internet/all books">Subject:Internet/all books</a></li><li><a href="/wiki/Category:Book:Wikibooks_Stacks/Books" title="Category:Book:Wikibooks Stacks/Books">Book:Wikibooks Stacks/Books</a></li><li><a href="/wiki/Category:Shelf:JavaScript_scripting_language/all_books" title="Category:Shelf:JavaScript scripting language/all books">Shelf:JavaScript scripting language/all books</a></li><li><a href="/wiki/Category:Shelf:Computer_programming/all_books" title="Category:Shelf:Computer programming/all books">Shelf:Computer programming/all books</a></li><li><a href="/wiki/Category:Shelf:Computer_programming_languages/all_books" title="Category:Shelf:Computer programming languages/all books">Shelf:Computer programming languages/all books</a></li><li><a href="/wiki/Category:Shelf:Computer_science/all_books" title="Category:Shelf:Computer science/all books">Shelf:Computer science/all books</a></li><li><a href="/wiki/Category:Department:Computing/all_books" title="Category:Department:Computing/all books">Department:Computing/all books</a></li><li><a href="/wiki/Category:Shelf:Internet/all_books" title="Category:Shelf:Internet/all books">Shelf:Internet/all books</a></li><li><a href="/wiki/Category:Shelf:Scripting_languages/all_books" title="Category:Shelf:Scripting languages/all books">Shelf:Scripting languages/all books</a></li><li><a href="/wiki/Category:Shelf:Web_development/all_books" title="Category:Shelf:Web development/all books">Shelf:Web development/all books</a></li><li><a href="/wiki/Category:Alphabetical/J" title="Category:Alphabetical/J">Alphabetical/J</a></li><li><a href="/wiki/Category:Half-finished_books" title="Category:Half-finished books">Half-finished books</a></li><li><a href="/wiki/Category:Books_by_completion_status/all_books" title="Category:Books by completion status/all books">Books by completion status/all books</a></li></ul></div></div> </div> </main> </div> <div class="mw-footer-container"> <footer id="footer" class="mw-footer" > <ul id="footer-info"> <li id="footer-info-lastmod"> This page was last edited on 17 June 2024, at 09:15.</li> <li id="footer-info-copyright">Text is available under the <a rel="nofollow" class="external text" href="//creativecommons.org/licenses/by-sa/4.0/">Creative Commons Attribution-ShareAlike License</a>; additional terms may apply. By using this site, you agree to the <a class="external text" href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Terms_of_Use">Terms of Use</a> and <a class="external text" href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy">Privacy Policy.</a></li> </ul> <ul id="footer-places"> <li id="footer-places-privacy"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy">Privacy policy</a></li> <li id="footer-places-about"><a href="/wiki/Wikibooks:Welcome">About Wikibooks</a></li> <li id="footer-places-disclaimers"><a href="/wiki/Wikibooks:General_disclaimer">Disclaimers</a></li> <li id="footer-places-wm-codeofconduct"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Universal_Code_of_Conduct">Code of Conduct</a></li> <li id="footer-places-developers"><a href="https://developer.wikimedia.org">Developers</a></li> <li id="footer-places-statslink"><a href="https://stats.wikimedia.org/#/en.wikibooks.org">Statistics</a></li> <li id="footer-places-cookiestatement"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Cookie_statement">Cookie statement</a></li> <li id="footer-places-mobileview"><a href="//en.m.wikibooks.org/w/index.php?title=JavaScript&mobileaction=toggle_view_mobile" class="noprint stopMobileRedirectToggle">Mobile view</a></li> </ul> <ul id="footer-icons" class="noprint"> <li id="footer-copyrightico"><a href="https://wikimediafoundation.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><img src="/static/images/footer/wikimedia-button.svg" width="84" height="29" alt="Wikimedia Foundation" loading="lazy"></a></li> <li id="footer-poweredbyico"><a href="https://www.mediawiki.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><img src="/w/resources/assets/poweredby_mediawiki.svg" alt="Powered by MediaWiki" width="88" height="31" loading="lazy"></a></li> </ul> </footer> </div> </div> </div> <div class="vector-settings" id="p-dock-bottom"> <ul></ul> </div><script>(RLQ=window.RLQ||[]).push(function(){mw.config.set({"wgHostname":"mw-web.codfw.main-694cf4987f-t4trx","wgBackendResponseTime":189,"wgPageParseReport":{"limitreport":{"cputime":"0.208","walltime":"0.411","ppvisitednodes":{"value":3888,"limit":1000000},"postexpandincludesize":{"value":70654,"limit":2097152},"templateargumentsize":{"value":10335,"limit":2097152},"expansiondepth":{"value":42,"limit":100},"expensivefunctioncount":{"value":4,"limit":500},"unstrip-depth":{"value":0,"limit":20},"unstrip-size":{"value":506,"limit":5000000},"entityaccesscount":{"value":0,"limit":400},"timingprofile":["100.00% 380.920 1 -total"," 79.66% 303.428 1 Template:Shelves"," 43.38% 165.233 1 Template:Subjects/leaf"," 42.67% 162.553 1 Template:Subjects/0"," 24.95% 95.028 38 Template:Parsable"," 23.58% 89.837 4 Template:Subjects/1"," 19.02% 72.448 6 Template:Subjects/2"," 17.54% 66.826 19 Template:Subjects/allbooks"," 14.17% 53.969 8 Template:Subjects/3"," 12.87% 49.010 1 Template:Shelf:Map"]},"scribunto":{"limitreport-timeusage":{"value":"0.152","limit":"10.000"},"limitreport-memusage":{"value":1669514,"limit":52428800}},"cachereport":{"origin":"mw-web.eqiad.main-5dc8bcfc84-jqjz8","timestamp":"20241112013147","ttl":2592000,"transientcontent":false}}});});</script> <script type="application/ld+json">{"@context":"https:\/\/schema.org","@type":"Article","name":"JavaScript","url":"https:\/\/en.wikibooks.org\/wiki\/JavaScript","sameAs":"http:\/\/www.wikidata.org\/entity\/Q2005","mainEntity":"http:\/\/www.wikidata.org\/entity\/Q2005","author":{"@type":"Organization","name":"Contributors to Wikimedia projects"},"publisher":{"@type":"Organization","name":"Wikimedia Foundation, Inc.","logo":{"@type":"ImageObject","url":"https:\/\/www.wikimedia.org\/static\/images\/wmf-hor-googpub.png"}},"datePublished":"2004-06-20T20:42:43Z","headline":"high-level programming language"}</script> </body> </html>