Thanks for suggestion, but I can't use your sign out. I have my own Login in webcontrol and i had copied your sign out code
FormsAuthentication.SignOut();
in my sign out function and add at top imported
<%@ Import Namespace="CuteChat" %>
as on your banner.ascx still i am getting error object required on LogOut on default page in javascript.
Have i to add something else also to resolve it.