Something

<!-- here starts my code, test with  the calendar-->
<asp:Button ID="btnShowDate" runat="server" Text="Button" onClick="ShowDate" /><br />
	
<atlas:updatepanel ID="TestDate" runat="server" >
	<Triggers>
		<atlas:ControlEventTrigger ControlID="btnShowDate"  EventName="Click" />
	</Triggers>	
	<asp:Textbox id="txtDate" runat="server"/>	
</atlas:updatepanel>
<!-- until here -->