title: jQuery.addClass not working
body: <p>This looks valid but it's not working.  I'd like the 'huh' div to become opaque when the menu is hovered over.  I tried this with fadein/out and it worked but just the once which was odd.</p>
  
  <pre><code> &lt;script type="text/javascript"&gt;
      $( function() {
          $('#menuNav').hover( function() {
              $('#huh').addClass('.opacity');
          }, function(){
              $('#huh').removeClass('.opacity');
          });
      });
  
  &lt;/script&gt;
  
  .opacity {
      opacity: 0.3;
  }
  </code></pre>