title: Deleting CSS Rule does not work in Firefox
body: <p>I am trying to delete the first css rule. </p>
  
  <p>However, this does not work in Firefox 3.6.28. Is this the same for everyone and why is this the case?</p>
  
  <pre><code>&lt;!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"&gt;
  &lt;html&gt;
      &lt;head&gt;
          &lt;title&gt;Test&lt;/title&gt;
          &lt;meta http-equiv="Content-Type" content="text/html;charset=utf-8" &gt;
          &lt;script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"&gt;&lt;/script&gt;
          &lt;script type="text/javascript"&gt;
  
              $(window).load(function(){
  
                  console.log(document.styleSheets);
                  document.styleSheets[0].deleteRule(0);
                  console.log(document.styleSheets); // same as the first console.log
  
              });
  
          &lt;/script&gt;
          &lt;style&gt;
              body{font-size:62.5%;}
              #mc{padding:310px 0 10px 162px; color:#fff;}
              #content{width:500px;}
              #header{padding-top:10px;}
              #banner{padding:10px 0}
          &lt;/style&gt;
      &lt;/head&gt;
      &lt;body&gt;
          Test JS
      &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <h2>Update</h2>
  
  <p>Just to clarify, the delete seems to be working however the <code>console.log</code> shows the same number of rules before and after the delete.</p>