title: Need help understanding a javascript function
body: <p>I'm hoping someone can explain the following usage of JavaScript.</p>
  <p>I have a page with a script that looks like this:</p>
  <pre><code>(function($){
       // code 
       // and stuff
  })(jQuery);
  </code></pre>
  <p>I'm trying to understand what this code does, specifically:</p>
  <ol>
  <li>The opening parenthesis at the start</li>
  <li>The usage of the <code>$</code> symbol</li>
  <li>The jQuery in parentheses at the end</li>
  </ol>
  <p>thanks!</p>