Can i use applet to cleanup session at server

Hi All,

I have a module in a web - application where my application login in some third-party tool (in background).
The problem is, if user closes the windows directly instead of log-off then it left the application logged-in in third-party tool.

I wanted to perform the same cleanup even on browser-close event.
for this i have tried with javascript and i have raised my hands.
But is ther any way via applet to intimate server so that i can perform cleanup.
If any one have done this please suggest.

Regards,
VijayS.