OK, so for some reason you have a mega mashup solution with ASP.net AJAX, jQuery and web forms. Perhaps you are just on the migration from AjaxControlToolkit to the jQuery UI framework – who knows!! Anyway, the problem is that when you post back with something like an UpdatePanel, you will find that your nicely setup jQuery stuff, like the datepicker for example will no longer work. You may have something like this… $(document).ready(function () { $(".date-edit").datepicker({ dateFormat: "dd/mm/yy",...