title: What does it mean to "export to the browser"
body: <p>The backbone.js <a href="http://documentcloud.github.com/backbone/docs/backbone.html" rel="nofollow">annotated source</a> describes the following piece of code </p>
  
  <pre><code>  var Backbone;
    if (typeof exports !== 'undefined') {
      Backbone = exports;
    } else {
      Backbone = root.Backbone = {};
    }
  </code></pre>
  
  <p>as "The top-level namespace. All public Backbone classes and modules will be attached to this. Exported for both CommonJS and the browser."</p>
  
  <p>What does "exported for the browser" mean in this context?</p>