If you have a question about a specific setup or using particular libraries or file layouts with requirejs, then it is best to ask that on [Stack Overflow using the requirejs tag](https://stackoverflow.com/questions/tagged/requirejs). New issues here are best used for bug reports that have test cases or examples.

RequireJS loads plain JavaScript files as well as more defined modules. It is

optimized for in-browser use, including in

in other JavaScript environments, like Rhino and

[Asynchronous Module](https://github.com/amdjs/amdjs-api/wiki/AMD)

API.

RequireJS uses plain script tags to load modules/files, so it should allow for

easy debugging. It can be used

so you can add it to your existing project without having to re-write your

JavaScript files.

you can run as part of your packaging steps for deploying your code. The

optimization tool can combine and minify your JavaScript files to allow for

better performance.

If the JavaScript file defines a JavaScript module via

of a module in a page. RequireJS also has a plugin system that supports features like

RequireJS does not have any dependencies on a JavaScript framework.

RequireJS works in IE 6+, Firefox 2+, Safari 3.2+, Chrome 3+, and Opera 10+.

</div>

<div id="footer" class="mono">

<span class="line">Open source: <a href="https://github.com/requirejs/requirejs/blob/master/LICENSE">new BSD or MIT licensed</a></span>

<span class="line">web design by <a href="http://andychung.me/">Andy Chung</a> &copy; 2011-2017</span>

</div>

<ul>

<li class="version">2.3.5 Docs (<a href="https://github.com/requirejs/requirejs/wiki/Upgrading-to-RequireJS-2.1">upgrade info</a>)</li>

</ul>

</div>

<div id="directory" class="section">

<h1>RequireJS API</h1>

<ul class="index mono">

<li class="hbox"><a href="#usage">Usage</a><span class="spacer boxFlex"></span><span class="sect">&sect;&sect; 1-1.3</span></li>

<ul>

});

//bar.js, which uses simplified CJS wrapping:

define(function (require, exports, module) {

//Will be the value 'large'

var size = module.config().size;

<div class="section">

<h2><a name="latest">Latest Release</a><span class="sectionMark">&sect; 1</span></h2>

<div class="subSection">

<h4 class="hbox">

<a name="requirejs">require.js 2.3.5</a>

<span class="boxFlex"></span>

<p>All you need to start using require.js in the browser.</p>

<h4 class="hbox">

<a name="rjs">r.js: Optimizer and Node/Rhino/Nashorn/xpcshell adapter</a>

<span class="boxFlex"></span>

<p>The r.js file allows you to run the optimizer as well as run modules in Node, Rhino, Nashorn or xpcshell.</p>

<h3 id="2-3-0">2.3.0</h3>

<p><a href="https://github.com/requirejs/alameda/releases/tag/1.1.0">alameda was also updated to 1.1.0</a> to include the same dependency searching change as requirejs 2.3.</p>

<p>Maintenance release. A change that may be noticeable:</p>

now correctly generates URLs for string values passed to it without an

extension. Previous versions of toUrl() would append a

".js" extension automatically. If you relied on that behavior, when you

<li><strong>Returning a function as the module value</strong>, particularly a constructor function, leads to better API design. Node has module.exports to allow this, but being able to use "return function (){}" is much cleaner. It means not having to get a handle on "module" to do module.exports, and it is a clearer code expression.</li>

<li><strong>Dynamic code loading</strong> (done in AMD systems via <a href="https://github.com/amdjs/amdjs-api/wiki/require">require([], function (){})</a>) is a basic requirement. CJS talked about it, had some proposals, but it was not fully embraced. Node does not have any support for this need, instead relying on the synchronous behavior of require(''), which is not portable to the web.</li>

<li><strong>Selectively mapping one module</strong> to load from another location makes it easy to provide mock objects for testing.</li>

<li>There should only be at most <strong>one IO action for each module</strong>, and it should be straightforward. Web browsers are not tolerant of multiple IO lookups to find a module. This argues against the multiple path lookups that Node does now, and avoiding the use of a package.json "main" property. Just use module names that map easily to one location based on the project's location, using a reasonable default convention that does not require verbose configuration, but allow for simple configuration when needed.</li>

<li>It is best if there is an <strong>"opt-in" call</strong> that can be done so that older JS code can participate in the new system.</li>

<li>Give an AMD loader a try. You have some choices:

<li><a href="https://github.com/cujojs/curl">curl</a></li>

<li><a href="https://github.com/zazl/lsjs">lsjs</a></li>

<li><a href="http://dojotoolkit.org/">Dojo</a> 1.7+</li>

<li>If you want to use AMD but still use the <strong>load one script at the bottom of the HTML page</strong> approach:

function makeError(id, msg, err, requireModules) {

e.requireType = id;

e.requireModules = requireModules;

if (err) {