How to track browser closing event?

Question

Hi Everyone,
I ran into a problem, which I thought at first would be a very easy thing to solve. Unfortunately, I spent few hours already reading through the forums posts and could not find the answer. Some say it is impossible to implement. I think there has got to be a solution to this problem.
I need to track user's login time into the JSP application and record both login and logoff timestamps. I had no problem with the login. Just instantiated my TimeTracker object on the index.jsp page and it writes a new row into the database every time user hits this page. However, things are different with the logoff. User can exit out in three dirrent ways. One is to click the "Exit" button, second is when session expires and the third is when "X" button of the browser is clicked and browser shuts down. I can control first two scenarious. I don't know what to do about the user closing the browser.
I tried capturing onCLose, onUnload or onBeforeUnload events but all of them are also invoked when window gets instantiated or when user clicks on a different page within the application. I also tried instantiating an applet within my JSP template and invalidate session inside its destroy() method but the problem here is that the applet gets destroyed every time a different page within the application is accessed.
I am ready to give up and just leave it as it is now, let the session expire on its own and take care of the logoff time.
Did anybody have similar problem and found the resolution?
Any help would be greatly appreciated.
Thanks,
YM

Answer 1

The common answer is that there is no good way to track the browser closing. A page can't tell the difference between the browser closing and simply navigating to a different page, so determining when the broswer is actually closed is a tough task. There have been some complex solutions in the past, but none seemed to be guaranteed to work, and as such, are pretty much useless for most applications.