Test Case Boilerplate
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HTML
<script src="http://code.jquery.com/ui/jquery-ui-git.js"></script>
<link rel="stylesheet" href="http://code.jquery.com/ui/jquery-ui-git.css">
<html>
<body>
<input id="foo" value="11/11/11">
<input id="foo2" value="11/11/111">
</body>
</html>
JavaScript
$('input').datepicker({
dateFormat: "mm/dd/yy"
});