Java EE (Java Enterprise Edition) General Discussion

if a user closes a browser instead of clicking on something like "logout", then, how the servlet can detect that the user exits out the application, and update the database accordingly, for example, the time the user spent for that application?

i tried to use javascript, onunload, but it will trigger every back, refresh, and any link clicking event. so i'm wonder, if there's a way a servelet can detect it directly.

thanks a lot.

cc