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<p class="summary"><strong>JavaScript</strong><sup>®</sup> (often shortened to <strong>JS</strong>) is a lightweight, interpreted, object-oriented language with <a href="https://en.wikipedia.org/wiki/First-class_functions" title="https://en.wikipedia.org/wiki/First-class_functions">first-class functions</a>, most known as the scripting language for Web pages, but <a class="external" href="https://en.wikipedia.org/wiki/JavaScript#Uses_outside_web_pages">used in many non-browser environments</a> as well such as <a class="external" href="https://nodejs.org/">node.js</a> or <a href="https://couchdb.apache.org/">Apache CouchDB</a>. It is a <a class="mw-redirect" href="https://en.wikipedia.org/wiki/Prototype-based_programming" title="Prototype-based">prototype-based</a>, multi-paradigm scripting language that is dynamic, and supports object-oriented, imperative, and functional programming styles. Read more <a href="/en-US/docs/Web/JavaScript/About_JavaScript">about JavaScript</a>.</p>

<p>The JavaScript standard is called <a href="/en-US/docs/JavaScript/Language_Resources">ECMAScript</a>. As of 2012, all modern browsers fully support ECMAScript 5.1. Older browsers support at least ECMAScript 3. On June 17, 2015, the sixth major version of ECMAScript was published. This version is officially called ECMAScript 2015, but is commonly referred to as ECMAScript 6 or ES6. The documentation we present covers ECMAScript 6 and we've already begun to cover the early bits of ECMAScript 7.</p>

<p>This section of the site is dedicated to the JavaScript language itself, the parts that are not specific to Web pages, or other host environments. For information about {{Glossary("API","APIs")}} specific to Web pages, please see <a href="/en-US/docs/Web/API">Web APIs</a> and <a href="/en-US/docs/Glossary/DOM">DOM</a>.</p>

<p>JavaScript is not to be confused with the&nbsp;<a href="https://en.wikipedia.org/wiki/Java_(programming_language)">Java programming language</a>. Java is a trademark or registered trademark of Oracle in the U.S. and other countries.</p>

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<h2 id="Tutorials">Tutorials</h2>

<p>Learn how to program with JavaScript with our guides and tutorials.</p>

<h3 id="Introductory">Introductory</h3>

<dl>
 <dt><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide">JavaScript Guide</a></dt>
 <dd>If you are new to JavaScript, this guide will walk you through the language.</dd>
 <dt><a href="/en-US/docs/Web/JavaScript/JavaScript_technologies_overview">JavaScript technologies overview</a></dt>
 <dd>Introduction to the web browser JavaScript landscape.</dd>
 <dt><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Introduction_to_Object-Oriented_JavaScript">Introduction to Object Oriented JavaScript</a></dt>
 <dd>Introduction to the concepts of object oriented programming in JavaScript.</dd>
</dl>

<h3 id="Intermediate">Intermediate</h3>

<dl>
 <dt><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/A_re-introduction_to_JavaScript">A re-introduction to JavaScript</a></dt>
 <dd>An overview for those who <em>think</em> they know about JavaScript.</dd>
</dl>

<dl>
 <dt><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures">JavaScript data structures</a></dt>
 <dd>Overview of available data structures in JavaScript.</dd>
 <dt><a href="/en-US/docs/Web/JavaScript/Equality_comparisons_and_sameness">Equality comparisons and sameness</a></dt>
 <dd>JavaScript provides three different value-comparison operations: strict equality using <code>===</code>, loose equality using <code>==</code>, and the {{jsxref("Global_Objects/Object/is", "Object.is()")}} method.</dd>
</dl>

<h3 id="Advanced">Advanced</h3>

<dl>
 <dt><a href="/en-US/docs/Web/JavaScript/Inheritance_and_the_prototype_chain">Inheritance and the prototype chain</a></dt>
 <dd>Explanation of the widely misunderstood and under-estimated prototype-based inheritance.</dd>
 <dt><a href="/en-US/docs/Web/JavaScript/Reference/Strict_mode">Strict mode</a></dt>
 <dd>A restricted variant of JavaScript.</dd>
 <dt><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Typed_arrays">JavaScript typed arrays</a></dt>
 <dd>JavaScript typed arrays provide a mechanism for accessing raw binary data.</dd>
 <dt><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Memory_Management">Memory Management</a></dt>
 <dd>Memory life cycle and garbage collection in JavaScript.</dd>
 <dt><a href="/en-US/docs/Web/JavaScript/EventLoop">Concurrency model and Event Loop</a></dt>
 <dd>JavaScript has a concurrency model based on an "event loop".</dd>
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<h2 id="Reference">Reference</h2>

<p>Browse the complete <a href="/en-US/docs/Web/JavaScript/Reference">JavaScript reference</a> documentation.</p>

<dl>
 <dt><a href="/en-US/docs/Web/JavaScript/Reference/Global_Objects">Standard objects</a></dt>
 <dd>Get to know standard built-in objects {{jsxref("Array")}}, {{jsxref("Boolean")}}, {{jsxref("Date")}}, {{jsxref("Error")}}, {{jsxref("Function")}}, {{jsxref("JSON")}}, {{jsxref("Math")}}, {{jsxref("Number")}}, {{jsxref("Object")}}, {{jsxref("RegExp")}}, {{jsxref("String")}}, {{jsxref("Map")}}, {{jsxref("Set")}}, {{jsxref("WeakMap")}} , {{jsxref("WeakSet")}}, and others.</dd>
 <dt><a href="/en-US/docs/Web/JavaScript/Reference/Operators">Expressions and operators</a></dt>
 <dd>Learn more about the behavior of JavaScript's operators {{jsxref("Operators/instanceof", "instanceof")}}, {{jsxref("Operators/typeof", "typeof")}}, {{jsxref("Operators/new", "new")}}, {{jsxref("Operators/this", "this")}}, the <a href="/en-US/docs/Web/JavaScript/Reference/Operators/Operator_Precedence">operator precedence</a>, and more.</dd>
 <dt><a href="/en-US/docs/Web/JavaScript/Reference/Statements">Statements and declarations</a></dt>
 <dd>Learn how {{jsxref("Statements/do...while", "do-while")}}, {{jsxref("Statements/for...in", "for-in")}}, {{jsxref("Statements/for...of", "for-of")}}, {{jsxref("Statements/try...catch", "try-catch")}}, {{jsxref("Statements/let", "let")}}, {{jsxref("Statements/var", "var")}}, {{jsxref("Statements/const", "const")}}, {{jsxref("Statements/if...else", "if-else")}}, {{jsxref("Statements/switch", "switch")}}, and more JavaScript statements and keywords work.</dd>
 <dt><a href="/en-US/docs/Web/JavaScript/Reference/Functions">Functions</a></dt>
 <dd>Learn how to work with JavaScript's functions to develop your applications.</dd>
</dl>

<h2 id="Tools_resources">Tools &amp; resources</h2>

<p>Helpful tools while writing and debugging your JavaScript code.</p>

<dl>
 <dt><a href="/en-US/docs/Tools">Firefox Developer Tools</a></dt>
 <dd><a href="/en-US/docs/Tools/Scratchpad">Scratchpad</a>, <a href="/en-US/docs/Tools/Web_Console">Web Console</a>, <a href="/en-US/docs/Tools/Profiler">JavaScript Profiler</a>, <a href="/en-US/docs/Tools/Debugger">Debugger</a>, and more.</dd>
 <dt><a class="external" href="https://www.getfirebug.com/">Firebug</a></dt>
 <dd>Edit, debug, and monitor CSS, HTML, and JavaScript live in any web page.</dd>
 <dt><a href="/en-US/docs/Web/JavaScript/Shells">JavaScript Shells</a></dt>
 <dd>A JavaScript shell allows you to quickly test snippets of JavaScript code.</dd>
 <dt><a href="https://togetherjs.com/">TogetherJS</a></dt>
 <dd>
 <p>Collaboration made easy.</p>
 </dd>
 <dt><a href="https://stackoverflow.com/questions/tagged/javascript">Stack Overflow</a></dt>
 <dd>Stack Overflow questions tagged with "JavaScript".</dd>
 <dt><a href="/en-US/docs/Web/JavaScript/New_in_JavaScript">JavaScript versions and release notes</a></dt>
 <dd>Browse JavaScript's feature history and implementation status.</dd>
 <dt><a href="https://jsfiddle.net/">JSFiddle</a></dt>
 <dd>Edit JavaScript, CSS, HTML and get live results. Use external resources and collaborate with your team online.</dd>
 <dd>&nbsp;</dd>
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