Calender Popup Calender

<%@ Control Language="VB" AutoEventWireup="false" CodeFile="DateUserControl.ascx.vb"
Inherits="UserControls_DateUserControl" %>

onclientClick="javascript:GetDate1('<%=txtDate.ClientId%>' ControlToValidate="txtDate" CssClass="ErrorMessage" EnableViewState="False" Display="Dynamic"> ErrorMessage="Date not valid" Display ="Dynamic" ValidationExpression ="^((((((0?[13578])|(1[02]))[\-\/\s]?((0?[1-9])|([1-2][0-9])|(3[01])))|(((0?[469])|(11))[\-\/\s]?((0?[1-9])|([1-2][0-9])|(30)))|(0?2[\-\/\s]?((0?[1-9])|([1-2][0-9]))))[\-\/\s]?\d{2}(([02468][048])|([13579][26])))|(((((0?[13578])|(1[02]))[\-\/\s]?((0?[1-9])|([1-2][0-9])|(3[01])))|(((0?[469])|(11))[\-\/\s]?((0?[1-9])|([1-2][0-9])|(30)))|(0?2[\-\/\s]?((0?[1-9])|(1[0-9])|(2[0-8]))))[\-\/\s]?\d{2}(([02468][1235679])|([13579][01345789]))))(\s(((0?[1-9])|(1[0-2]))\:([0-5][0-9])((\s)|(\:([0-5][0-9])\s))([AM|PM|am|pm]{2,2})))?$">