I've posted the following question to SO, but thought there might be a server based solution. http://stackoverflow.com/questions/9053964/php-script-with-sleep-does-not-exit-on-connection-close I'm running an Ubuntu VPS to run this script, and I'm trying to get the script to die when the user closes the window/tab of his browser. There are several PHP based functions to see if the connection is still open, but none works (trust me, tested them all). Any creative ideas on how I can do this through the server maybe?