Date.js
Stuff for testing Date.js
HTML
<script src="http://www.datejs.com/build/date.js"></script>
<div id="datepicker"></div>
<div id="result"></div>
JavaScript
$( "#datepicker" ).datepicker();
$("#datepicker").change(
function() {
var x = new Date.parse($( "#datepicker" ).datepicker("getDate"));
var result = x;//.last().monday();
$("#result").html(result.toString("yyyy/MM/dd"));
});