Ajax calender extender not working

Hi

    I m working on web application and  i m using calender extender ,i want to create like  when user click on text box calender should popup

following is the code i used but nothing is happening

<asp:ToolkitScriptManager ID="ToolkitScriptManager1" runat="server">
</asp:ToolkitScriptManager>

<asp:CalendarExtender ID="CalendarExtender1" runat="server" TargetControlID="TextBox2" PopupPosition="Right" Format="dd/MM/yyyy">
    </asp:CalendarExtender>

but the same code i used in another application it works fine pls give your valuable  suggestion