PHP script terminating

I'm running PHP 4.0.3 on sparc solaris 2.6 How to terminate PHP script on user request? I tried setting ignore_user_abort(0) and if I hit the stop button the script wasn't terminated.. it doesn;t seem to work under IE either I tried many times with different settings, no results.. another issue, how to free the memory allocated to PHP script, even when the script is finished, its process (one of httpd) remains, it's sleeping but still takes up memory resources (in my case up to 30MB) please help me with any ideas rgrds greg