<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<script src="//ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<link rel="stylesheet" href="//ajax.googleapis.com/ajax/libs/jqueryui/1.11.2/themes/smoothness/jquery-ui.css" />
<script src="//ajax.googleapis.com/ajax/libs/jqueryui/1.11.2/jquery-ui.min.js"></script>
<script>
$(document).ready(function () {
$("#txt_date").datepicker();
});
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
<h3>Click to select a date :</h3>
<asp:textbox ID="txt_date" runat="server"></asp:textbox>
</div>
</form>
</body>
</html>