Possible Duplicate:
Firefox session cookies
I'm creating a website in which users are allowed to view certain pages only when logged in. To accomplish this, I check to see if $_SESSION['uid'] is set and if it is not, I send the user back to the homepage instead of to the private page. However, after the user closes his browser, $_SESSION['uid'] stays set and so the user is allowed to view the private page without having to log in again. Why is this? Why is the $_SESSION['uid'] variable staying set across browser sessions? The site works properly in Chrome but not FF.