title: jquery ui - referencing dropped element
body: <p>So I know that if an element is droppable, then you can set an option like:</p>
  
  <pre><code>drop: function(){
   alert('something was dropped');
  }
  </code></pre>
  
  <p>but how can I set it so I can reference the element dropped onto it, so I could do something like this:</p>
  
  <pre><code>drop: function(){
   alert(elementId + ' was dropped');
  }
  </code></pre>
  
  <p>Thanks.</p>