The example below shows how to set Monday as the first day of calendar:
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>DateBox - jQuery EasyUI Demo</title>
<link rel="stylesheet" type="text/css" href="http://www.jeasyui.com/easyui/themes/default/easyui.css">
<script type="text/javascript" src="http://www.jeasyui.com/easyui/jquery-1.7.2.min.js"></script>
<script type="text/javascript" src="http://www.jeasyui.com/easyui/jquery.easyui.min.js"></script>
<script>
$.fn.calendar.defaults.firstDay = 1;
</script>
</head>
<body>
<input class="easyui-datebox" value="5/3/2012"></input>
</body>
</html>
