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data-glean="homepage_hero: js">JavaScript</a>, since 2005.</p> <div class="homepage-hero-search"> <form action="/en-US/search" class="search-form search-widget" id="hp-search-form" role="search"> <label id="hp-search-label" for="hp-search-input" class="visually-hidden">Search MDN</label><input aria-activedescendant="" aria-autocomplete="list" aria-controls="hp-search-menu" aria-expanded="false" aria-labelledby="hp-search-label" autocomplete="off" id="hp-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="hp-search-menu" role="listbox" aria-labelledby="hp-search-label"></div> </form> </div> </section> <div class="mandala-container homepage-hero-bg" aria-hidden="true"> <div class="mandala-translate"> <div class="mandala-svg-container"> <svg width="675" height="675" viewbox="0 0 675 675" fill="none" xmlns="http://www.w3.org/2000/svg" class="mandala"> <title>Mandala</title><defs> <path d="M337.5,337.5 m-320,0 a320,320 0 1,1 640,0 a320,320 0 1,1 -640,0" id="circle1"></path> <path d="M337.5,337.5 m-280,0 a280,280 0 1,1 560,0 a280,280 0 1,1 -560,0" id="circle2"></path> <path d="M337.5,337.5 m-240,0 a240,240 0 1,1 480,0 a240,240 0 1,1 -480,0" id="circle3"></path> <path d="M337.5,337.5 m-200,0 a200,200 0 1,1 400,0 a200,200 0 1,1 -400,0" id="circle4"></path> <path d="M337.5,337.5 m-160,0 a160,160 0 1,1 320,0 a160,160 0 1,1 -320,0" id="circle5"></path> </defs><text dy="70" textlength="2010"> <textpath textlength="2010" href="https://developer-mozilla-org.translate.goog/en-US/?_x_tr_sl=pl&_x_tr_tl=no&_x_tr_hl=en-GB#circle1"> / <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan> / <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan> / <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan> / <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan> / <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan> / <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan> / <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan> </textpath> </text><text dy="70" textlength="1760"> <textpath textlength="1760" href="https://developer-mozilla-org.translate.goog/en-US/?_x_tr_sl=pl&_x_tr_tl=no&_x_tr_hl=en-GB#circle2"> + <tspan> + </tspan>+ <tspan> + </tspan>+ <tspan> + </tspan> + <tspan> + </tspan>+ <tspan> + </tspan>+ <tspan> + </tspan> + <tspan> + </tspan>+ <tspan> + </tspan>+ <tspan> + </tspan> + <tspan> + </tspan>+ <tspan> + </tspan>+ <tspan> + </tspan> + <tspan> + </tspan>+ <tspan> + </tspan>+ <tspan> + </tspan> + <tspan> + </tspan>+ <tspan> + </tspan>+ <tspan> + </tspan> + <tspan> + </tspan>+ <tspan> + </tspan>+ <tspan> + </tspan> </textpath> </text><text dy="70" textlength="1507"> <textpath textlength="1507" href="https://developer-mozilla-org.translate.goog/en-US/?_x_tr_sl=pl&_x_tr_tl=no&_x_tr_hl=en-GB#circle3"> <tspan> { </tspan>{ <tspan> { </tspan>{ <tspan> } </tspan>} <tspan> } </tspan>} <tspan> { </tspan>{ <tspan> { </tspan>{ <tspan> } </tspan>} <tspan> } </tspan>} <tspan> { </tspan>{ <tspan> { </tspan>{ <tspan> } </tspan>} <tspan> } </tspan>} <tspan> { </tspan>{ <tspan> { </tspan>{ <tspan> } </tspan>} <tspan> } </tspan>} <tspan> { </tspan>{ <tspan> { </tspan>{ <tspan> } </tspan>} <tspan> } </tspan>} <tspan> { </tspan>{ <tspan> { </tspan>{ <tspan> } </tspan>} <tspan> } </tspan>} </textpath> </text><text dy="70" textlength="1257"> <textpath textlength="1257" href="https://developer-mozilla-org.translate.goog/en-US/?_x_tr_sl=pl&_x_tr_tl=no&_x_tr_hl=en-GB#circle4"> ../../ ../../ ../../ ../../ ../../ ../../ ../../ </textpath> </text><text dy="70" textlength="1005"> <textpath textlength="1005" href="https://developer-mozilla-org.translate.goog/en-US/?_x_tr_sl=pl&_x_tr_tl=no&_x_tr_hl=en-GB#circle5"> <tspan> <> </tspan></> <tspan> <> </tspan></> <tspan> <> </tspan></> <tspan> <> </tspan></> <tspan> <> </tspan></> <tspan> <> </tspan></> <tspan> <> </tspan></> <tspan> <> </tspan></> <tspan> <> </tspan></> <tspan> <> </tspan></> <tspan> <> </tspan></> <tspan> <> </tspan></> <tspan> <> </tspan></> <tspan> <> </tspan></> <tspan> <> </tspan></> <tspan> <> </tspan></> </textpath> </text> </svg> </div> </div> </div> </div> <section class="place hp-main"></section> <div class="featured-articles"> <h2>Featured articles</h2> <div class="tile-container"> <div class="article-tile"> <a href="https://developer-mozilla-org.translate.goog/en-US/blog/?_x_tr_sl=pl&_x_tr_tl=no&_x_tr_hl=en-GB" class="tile-tag" data-glean="homepage: article_tag 1">Blog</a> <h3 class="tile-title"><a href="https://developer-mozilla-org.translate.goog/en-US/blog/mdn-scrimba-partnership/?_x_tr_sl=pl&_x_tr_tl=no&_x_tr_hl=en-GB" data-glean="homepage: article 1">MDN partners with Scrimba to enhance web development learning</a></h3> <p>We have chosen Scrimba as a course partner for the MDN Curriculum. This blog post explores what the partnership means practically, and how we will provide an even better web education experience together.</p> </div> <div class="article-tile"> <a href="https://developer-mozilla-org.translate.goog/en-US/blog/?_x_tr_sl=pl&_x_tr_tl=no&_x_tr_hl=en-GB" class="tile-tag" data-glean="homepage: article_tag 2">Blog</a> <h3 class="tile-title"><a href="https://developer-mozilla-org.translate.goog/en-US/blog/learn-javascript-console-methods/?_x_tr_sl=pl&_x_tr_tl=no&_x_tr_hl=en-GB" data-glean="homepage: article 2">Developer essentials: JavaScript console methods</a></h3> <p>The JavaScript console is an essential tool for web development. Learn new and fun ways to use the console to display data and debug your code.</p> </div> <div class="article-tile"> <a href="https://developer-mozilla-org.translate.goog/en-US/blog/?_x_tr_sl=pl&_x_tr_tl=no&_x_tr_hl=en-GB" class="tile-tag" data-glean="homepage: article_tag 3">Blog</a> <h3 class="tile-title"><a href="https://developer-mozilla-org.translate.goog/en-US/blog/introduction-to-web-sustainability/?_x_tr_sl=pl&_x_tr_tl=no&_x_tr_hl=en-GB" data-glean="homepage: article 3">Introduction to web sustainability</a></h3> <p>What can web designers and developers do to build a more sustainable web? This post explores the environmental impacts of web technologies and looks at some of the ways we can build greener websites.</p> </div> <div class="article-tile"> <a href="https://developer-mozilla-org.translate.goog/en-US/docs/Web/API?_x_tr_sl=pl&_x_tr_tl=no&_x_tr_hl=en-GB" class="tile-tag" data-glean="homepage: article_tag 4">Web APIs</a> <h3 class="tile-title"><a href="https://developer-mozilla-org.translate.goog/en-US/docs/Web/API/CSS_Custom_Highlight_API?_x_tr_sl=pl&_x_tr_tl=no&_x_tr_hl=en-GB" data-glean="homepage: article 4">CSS Custom Highlight API</a></h3> <p>The CSS Custom Highlight API provides a mechanism for styling arbitrary text ranges on a document by using JavaScript to create the ranges, and CSS to style them.</p> </div> </div> </div> <section class="latest-news"> <h2>Latest news</h2> <ul class="news-list"> <li class="news-item"><p class="news-title"><span><a href="https://developer-mozilla-org.translate.goog/en-US/blog/mdn-scrimba-partnership/?_x_tr_sl=pl&_x_tr_tl=no&_x_tr_hl=en-GB" data-glean="homepage: news 1">MDN partners with Scrimba to enhance web development learning</a></span><span><a class="news-source" href="https://developer-mozilla-org.translate.goog/en-US/blog/?_x_tr_sl=pl&_x_tr_tl=no&_x_tr_hl=en-GB" data-glean="homepage: news_source 1">developer.mozilla.org</a></span></p><span class="news-date">5 months ago</span></li> <li class="news-item"><p class="news-title"><span><a href="https://developer-mozilla-org.translate.goog/en-US/blog/mdn-http-observatory-launch/?_x_tr_sl=pl&_x_tr_tl=no&_x_tr_hl=en-GB" data-glean="homepage: news 2">Introducing the MDN HTTP Observatory</a></span><span><a class="news-source" href="https://developer-mozilla-org.translate.goog/en-US/blog/?_x_tr_sl=pl&_x_tr_tl=no&_x_tr_hl=en-GB" data-glean="homepage: news_source 2">developer.mozilla.org</a></span></p><span class="news-date">5 months ago</span></li> <li class="news-item"><p class="news-title"><span><a href="https://developer-mozilla-org.translate.goog/en-US/blog/mdn-curriculum-launch/?_x_tr_sl=pl&_x_tr_tl=no&_x_tr_hl=en-GB" data-glean="homepage: news 3">Lift-off: The MDN Curriculum launch</a></span><span><a class="news-source" href="https://developer-mozilla-org.translate.goog/en-US/blog/?_x_tr_sl=pl&_x_tr_tl=no&_x_tr_hl=en-GB" data-glean="homepage: news_source 3">developer.mozilla.org</a></span></p><span class="news-date">9 months ago</span></li> </ul> </section> <section class="recent-contributions"> <h2>Recent contributions</h2> <ul class="contribution-list"> <li class="request-item"><p class="request-title"><a href="https://translate.google.com/website?sl=pl&tl=no&hl=en-GB&u=https://github.com/mdn/translated-content/pull/24975" data-glean="homepage: contribution 1">[ru] update `Web/JavaScript/Reference/Global_Objects/Number/isSafeInteger` translation</a><span><a class="request-repo" href="https://translate.google.com/website?sl=pl&tl=no&hl=en-GB&u=https://github.com/mdn/translated-content" data-glean="homepage: contribution_repo 1">mdn/translated-content</a></span></p><span class="request-date">5 hours ago</span></li> <li class="request-item"><p class="request-title"><a href="https://translate.google.com/website?sl=pl&tl=no&hl=en-GB&u=https://github.com/mdn/content/pull/36862" data-glean="homepage: contribution 2">chore(http): Refresh headers ~[s->x]</a><span><a class="request-repo" href="https://translate.google.com/website?sl=pl&tl=no&hl=en-GB&u=https://github.com/mdn/content" data-glean="homepage: contribution_repo 2">mdn/content</a></span></p><span class="request-date">8 hours ago</span></li> <li class="request-item"><p class="request-title"><a href="https://translate.google.com/website?sl=pl&tl=no&hl=en-GB&u=https://github.com/mdn/content/pull/37164" data-glean="homepage: contribution 3">Bump lint-staged from 15.2.10 to 15.2.11</a><span><a class="request-repo" href="https://translate.google.com/website?sl=pl&tl=no&hl=en-GB&u=https://github.com/mdn/content" data-glean="homepage: contribution_repo 3">mdn/content</a></span></p><span class="request-date">11 hours ago</span></li> <li class="request-item"><p class="request-title"><a href="https://translate.google.com/website?sl=pl&tl=no&hl=en-GB&u=https://github.com/mdn/content/pull/37162" data-glean="homepage: contribution 4">chore: Replace LandingPageListSubpages with SubpagesWithSummaries macro</a><span><a class="request-repo" href="https://translate.google.com/website?sl=pl&tl=no&hl=en-GB&u=https://github.com/mdn/content" data-glean="homepage: contribution_repo 4">mdn/content</a></span></p><span class="request-date">13 hours ago</span></li> <li class="request-item"><p class="request-title"><a href="https://translate.google.com/website?sl=pl&tl=no&hl=en-GB&u=https://github.com/mdn/content/pull/37156" data-glean="homepage: contribution 5">Experimental features fixes </a><span><a class="request-repo" href="https://translate.google.com/website?sl=pl&tl=no&hl=en-GB&u=https://github.com/mdn/content" data-glean="homepage: contribution_repo 5">mdn/content</a></span></p><span class="request-date">13 hours ago</span></li> <li class="request-item"><p class="request-title"><a href="https://translate.google.com/website?sl=pl&tl=no&hl=en-GB&u=https://github.com/mdn/content/pull/37141" data-glean="homepage: contribution 6">Update the rust version for rust wasm tutorial</a><span><a class="request-repo" href="https://translate.google.com/website?sl=pl&tl=no&hl=en-GB&u=https://github.com/mdn/content" data-glean="homepage: contribution_repo 6">mdn/content</a></span></p><span class="request-date">14 hours ago</span></li> <li class="request-item"><p class="request-title"><a href="https://translate.google.com/website?sl=pl&tl=no&hl=en-GB&u=https://github.com/mdn/translated-content/pull/24963" data-glean="homepage: contribution 7">zh-CN: create `userScripts`</a><span><a class="request-repo" href="https://translate.google.com/website?sl=pl&tl=no&hl=en-GB&u=https://github.com/mdn/translated-content" data-glean="homepage: contribution_repo 7">mdn/translated-content</a></span></p><span class="request-date">a day ago</span></li> <li class="request-item"><p class="request-title"><a href="https://translate.google.com/website?sl=pl&tl=no&hl=en-GB&u=https://github.com/mdn/translated-content/pull/24968" data-glean="homepage: contribution 8">zh-CN: create `userScripts.onBeforeScript`</a><span><a class="request-repo" href="https://translate.google.com/website?sl=pl&tl=no&hl=en-GB&u=https://github.com/mdn/translated-content" data-glean="homepage: contribution_repo 8">mdn/translated-content</a></span></p><span class="request-date">a day ago</span></li> <li class="request-item"><p class="request-title"><a href="https://translate.google.com/website?sl=pl&tl=no&hl=en-GB&u=https://github.com/mdn/translated-content/pull/24936" data-glean="homepage: contribution 9">zh-CN: create `management.onEnabled()`</a><span><a class="request-repo" href="https://translate.google.com/website?sl=pl&tl=no&hl=en-GB&u=https://github.com/mdn/translated-content" data-glean="homepage: contribution_repo 9">mdn/translated-content</a></span></p><span class="request-date">a day ago</span></li> <li class="request-item"><p class="request-title"><a href="https://translate.google.com/website?sl=pl&tl=no&hl=en-GB&u=https://github.com/mdn/translated-content/pull/24941" data-glean="homepage: contribution 10">zh-CN: create `management.getPermissionWarningsByManifest()`</a><span><a class="request-repo" href="https://translate.google.com/website?sl=pl&tl=no&hl=en-GB&u=https://github.com/mdn/translated-content" data-glean="homepage: contribution_repo 10">mdn/translated-content</a></span></p><span class="request-date">a day ago</span></li> </ul> </section> <div class="contributor-spotlight dark"> <div class="wrapper"> <div class="text-col"> <h3>Contributor Spotlight</h3><a class="contributor-name" href="https://developer-mozilla-org.translate.goog/en-US/community/spotlight/hochan-lee?_x_tr_sl=pl&_x_tr_tl=no&_x_tr_hl=en-GB">HoChan Lee</a> <blockquote> <span class="icon icon-quote "></span>MDN is a large, open community where everyone is welcome. It offers a great opportunity to organize thoughts through writing, while sharing and expanding knowledge by engaging with a diverse group of people throughout the contribution process. </blockquote><a href="https://developer-mozilla-org.translate.goog/en-US/community?_x_tr_sl=pl&_x_tr_tl=no&_x_tr_hl=en-GB" class="spotlight-cta">Get involved →</a> </div> <figure class="contributor-graphic"> <img loading="lazy" width="512" height="323" src="/static/media/mdn_contributor.14a24dcfda486f000754.png" alt="Tiled Mozilla Logo"> </figure> </div> <div class="mandala-container " aria-hidden="true"> <div class="mandala-translate"> <div class="mandala-svg-container"> <svg width="675" height="675" viewbox="0 0 675 675" fill="none" xmlns="http://www.w3.org/2000/svg" class="mandala"> <title>Mandala</title><defs> <path d="M337.5,337.5 m-320,0 a320,320 0 1,1 640,0 a320,320 0 1,1 -640,0" id="circle1"></path> <path d="M337.5,337.5 m-280,0 a280,280 0 1,1 560,0 a280,280 0 1,1 -560,0" id="circle2"></path> <path d="M337.5,337.5 m-240,0 a240,240 0 1,1 480,0 a240,240 0 1,1 -480,0" id="circle3"></path> <path d="M337.5,337.5 m-200,0 a200,200 0 1,1 400,0 a200,200 0 1,1 -400,0" id="circle4"></path> <path d="M337.5,337.5 m-160,0 a160,160 0 1,1 320,0 a160,160 0 1,1 -320,0" id="circle5"></path> </defs><text dy="70" textlength="2010"> <textpath textlength="2010" href="https://developer-mozilla-org.translate.goog/en-US/?_x_tr_sl=pl&_x_tr_tl=no&_x_tr_hl=en-GB#circle1"> / <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan> / <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan> / <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan> / <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / </tspan> / <tspan> / </tspan>/ <tspan> / </tspan>/ <tspan> / 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