jQuery UI: Date Picker
Date Picker
HTML
<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.18/themes/mint-choc/jquery-ui.css">
<input type="text" id="d" />
<div id="z"></div>
JavaScript
$('#z').datepicker({
inline: true,
altField: '#d'
});
$('#d').change(function(){
$('#z').datepicker('setDate', $(this).val());
});