before closing the Application browser should prompt conformation
<p>I have a small requirement..</p>

<p>if the user dint sign off or log off then he try's to close the browser IE clicking on 'X' (top right of IE or Firefox browser ) then i need to ask a conformation message like "Are you sure you want to close ?" ...
I am using Master page in my application and i tried the event : "window.onbeforeunload " in my master page its works fine, shows an alert(conformation) message. but if i press back button on the browser(IE on IE or Firefox) then also its firing(but it should not) is there any way to full fill my requirement ..I hope i had explained u clearly...if not pl z let me know........</p>

<p>what i mean to say is.. if the Session("USerid") is active or if it contains any value ie.
Session("USerid")="XXX"
at that moment if user trys to close the browse(click in 'X'/Close button browser either IE or Firefox ) it should give prompt a message "are u sure do u want to close?"..</p>
