title: What does prototype mean here in the jQuery source code?
body: <p>As an example, copied from jQuery 1.2.6:</p>
  
  <pre><code>jQuery.fn = jQuery.prototype = {
      init: function( selector, context ) {
          // Make sure that a selection was provided
          selector = selector || document;
          ..........
      },
  };
  </code></pre>
  
  <p>I have read some posts here like <a href="https://stackoverflow.com/questions/3781373/javascript-what-are-extend-and-prototype-used-for">JavaScript: What are .extend and .prototype used for?</a> and know a prototype can be used in a subclass to extend some methods.</p>
  
  <p>But I cannot understand the usage in the above snippet from jQuery.</p>
  
  <p>Are there any canonical documents describing the prototype?</p>
  
  <p>Thanks.</p>