Ajax Calander Not Working

Question

Dear All,

I am new to ajax calender control.

here my code is:

<asp:TextBox ID="txtActDate" runat="server" CssClass="textSmallmand"></asp:TextBox>
<ajax:CalendarExtender ID="calActDate" runat="server" TargetControlID="txtActDate" PopupButtonID="imgCal" Format="dd/mm/yyyy">
</ajax:CalendarExtender>
<asp:ImageButton ID="imgCal" runat="server" Height="19px" ImageUrl="~/date_picker2.gif" Width="34px" CausesValidation="False" />

the problem is all controls are displaying, but when i click the Imagebutton, the calander control is not displaying.

Can anyone help?

Thanks in Advance