check this. Click demo button to see it working
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title></title>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.6/jquery.min.js" type = "text/javascript"></script>
<script src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/jquery-ui.min.js" type = "text/javascript"></script>
<link href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/themes/base/jquery-ui.css" rel = "Stylesheet" type="text/css" />
<script type = "text/javascript">
$(function () {
$("#txtDate").datepicker({
onSelect: function (date, obj) {
alert("You selected: " + date);
},
showOn: 'button',
buttonImageOnly: true,
buttonImage: 'http://jqueryui.com/demos/datepicker/images/calendar.gif'
});
});
</script>
</head>
<body>
<form id="form1">
<input type = "text" id = "txtDate" />
</form>
</body>
</html>
Demo