Sortserialize returns nothing

Sortserialize returns nothing

I'm trying to serialize, but I'm only getting an empty alert box.
I get no error message, it's just empty. Please help!

<script>
  $(document).ready(function(){
    $("#myList").sortable({
      update : function(e, ui)
      {
         serialize("#myList");
      }
   });
  });

function serialize(s)
{
   serial = jQuery.SortSerialize(s);
   alert(serial.hash);
};
  </script>
  <style>ul { list-style: none; }
li { background: #727EA3; color: #FFF; width: 100px; margin: 5px; font-size: 10px; font-family: Arial; padding: 3px; }</style>
</head>
<body>

<ul id="myList">
       <li id="11">Item 1</li>
       <li id="23">Item 2</li>
       <li id="33">Item 3</li>
       <li id="44">Item 4</li>
</ul>