title: jquery droppable - nested divs, get target id
body: <p>I have something like this:</p>
  
  <pre><code>$('#mover' ).draggable({});
  $('div').droppable({
      drop: function(event, ui) {
          console.log(event.target.id)
      }
  </code></pre>
  
  <p>then
      </p>
  
  <pre><code>&lt;div id="container"&gt;
      &lt;div id="target_1"&gt;&lt;/div&gt;
      &lt;div id="target_2"&gt;&lt;/div&gt;
      &lt;div id="target_3"&gt;&lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>When I drop mover on a div "container" is returned.  how do I return instead the lowest child that the item was dropped on?</p>