The following example aborts the xmlhttp object but doesn't stop the web server's process (yet). Anyone who knows how to really stop the server processing the data, please let me know at: mail (at) pietsieg.com and I'll be happy to finish the example.
Clicking the Abort Request button calls into the abort() method of the xmlhttp object, and shows a message.
abort()
Click the following button to start a process on the web server: