Php :: Passing Variable FROM Flash To HTML?

I have a rather simple flash application users can make a quick username when connected, and the username is created inside the flash swf.

Now, I have a cron job deleting inactive usernames every ten minutes (on my mysql database where these usernames are all stored and accessed by the other people online) which is fine. But it can still get cluttered up if a bunch of people sign off at once, there is still that 10 minute window before the cron job clears them.

The users have an option to click log out in the flash application which is fine and works great. But of course many choose not to click log off they just click the browser x.

I've looked into onbeforeunload and jquery's .unload but I still need a way to get the username variable that's IN flash INTO the HTML, then use a php script to run the delete username mysql query.

If not, any insight on how I might pass the username variable to the html to hold onto it after the user makes their username so it can be involved with the .unload function running the php script?

EDIT::::: Maybe is there a way to create a UNIQUE string of numbers with php then pass that var to flash to include with the mysql row then since i already have that var since it was created on the html side, just along with the unload, have it delete the row that has that unique id?

If anyone things this idea would be the best approach, and if i used something like md5(uniqid(microtime()) . $_SERVER['REMOTE_ADDR'] . $_SERVER['HTTP_USER_AGENT']) to make a random iD how could i go about storing the result in a var i could place in the flash vars param then again in the jquery unload or javascript onbeforeunload if that would be better .