jQuery UI date picker (click event)

HTML

<script src="http://codeorigin.jquery.com/ui/1.10.3/jquery-ui.min.js"></script>
<link rel="stylesheet" href="http://codeorigin.jquery.com/ui/1.10.3/themes/redmond/jquery-ui.css">
<input type="text" id="datepicker" />

JavaScript

$( "#datepicker").datepicker();

$( "#datepicker").on('change', function(){
    alert('lala!');
});