[jQuery] Problems with sortable()

[jQuery] Problems with sortable()


Can someone tell me why serialize returns nothing?
<ul id="sort">
<li id="1">123</li>
<li id="2">abc </li>
<li id="3">456</li>
<li id="4">xyz</li>
</ul>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/
libs/jquery/1.2.6/jquery.min.js"></script>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/
libs/jqueryui/1.5.2/jquery-ui.js"></script>
<script type="text/javascript">
$('#sort').sortable({
cursor: 'move',
axis: 'y',
update: function() {
sorted = $(this).sortable("serialize", 'id');
alert (sorted);
}
});
</script>