ConfirmButtonExtender not work on remote server !

Hello,

In my web project while I'm working on local computer the ConfirmButtonExtender control works fine, but on remote server ( production server ) the control not working on all pages ( click event fires without confirm message ) .

ASP code :

<asp:LinkButton runat="server" ID="lnkLogout" CausesValidation="false" OnClick="lnkLogout_Click">
  Log Out</asp:LinkButton>

 <asp:ConfirmButtonExtender ID="LogExtender" runat="server"
                                        ConfirmText="Are you sure to Logout ?" TargetControlID="lnkLogout" Enabled="true">
                                    </asp:ConfirmButtonExtender>

C# code :

Session.RemoveAll();
Session.Abandon();
Response.Redirect(System.Web.VirtualPathUtility.ToAbsolute("~/" + Modules.PO.URLCenter.LoginEn));

* note : if I use following approach it works fine :

lnkLogout.OnClientClick = "return confirm('are you sure to logout ?');";

Thanks in advance,