suppose i loggedIn in web application, then it open with new session.
i have done database updates on session time out. i have given 20 min time out. also i have called session.abondon() on direclty close the browser. but direct close is not detecting in mozilla, but that's no probelm, although u closes browser in mozilla, your session will expire after 20 min.
but suppose if u logged in again before previous session's time out to occur, u will be logged in with new session.
and when prev. session expires then it will change update database.
then even if u loggen in then ur online status will be offline b'caz it has changed by prev. session