I need a method to monitor user edit sessions, and one of the solutions I\'m reviewing will have me using an unload event to send an ajax request to inform the
You'll have to do your own testing about whether or not your particular scenario works with the time you have in unload, but making the AJAX request is pretty fast, since AJAX is asynchronous. You just send the request and then you're done! (Maybe you'll have to clear the request object you just created, though.)
If you wanted to verify that the AJAX request made it, then you'd have to worry more/use the async:false option (like this discussion indicates). But, just sending is a quick boom-and-you're-done operation.