title: jQuery UI Sortable does not serialize/toArray child elements
body: <p>I have the following list and when I call <code>toArray</code> or <code>serialize</code> it only offers me the parent <code>&lt;li&gt;</code>.  I am trying to get hold of the whole hierarchy so I can store this information into a self referencing heirachy table in the database.  The result here shows item_1,q_6,a_7,g_8. Where is item_3,item_4,item_5.</p>
  
  <p>Thanks</p>
  
  <pre><code>&lt;div id="example5"&gt;
      &lt;ul&gt;
           &lt;li id="item_1"&gt;Item 1
              &lt;ul id="item_2"&gt;
                  &lt;li id="item_3"&gt;Item 1 1&lt;ul&gt;&lt;/ul&gt;&lt;/li&gt;
                  &lt;li id="item_4"&gt;Item 1 2&lt;ul&gt;&lt;/ul&gt;&lt;/li&gt;
                  &lt;li id="item_5"&gt;Item 1 3&lt;ul&gt;&lt;/ul&gt;&lt;/li&gt;
               &lt;/ul&gt;
           &lt;/li&gt;
           &lt;li  id="q_6"&gt;Item 2&lt;ul&gt;&lt;/ul&gt;&lt;/li&gt;
           &lt;li  id="a_7"&gt;Item 3&lt;ul&gt;&lt;/ul&gt;&lt;/li&gt;
           &lt;li  id="g_8"&gt;Item 4&lt;ul&gt;&lt;/ul&gt;&lt;/li&gt;
      &lt;/ul&gt;
  &lt;/div&gt;
  
  &lt;button id="fred"&gt;Click&lt;/button&gt;
  
  $("#fred").click(function () {
     //var result = $('#example5 ul').sortable('toArray');
     var result = $('#example5 ul').sortable('serialize'); //Neither work
  
     alert(result);
  });
  </code></pre>