I have an ASPX page which when is submitted into a new tab starts a server side process. Sometimes the process takes too long and a user closes the tab the page is running in. However, the process continues running and that creates a big problem. My question is why the process continues running and how can I kill it when the tab is closed. I do have a code in the code behind where I can kill the process, I just can't find a way of executing it. Please, help. Release is coming. Closing Browser actually help.

Thanks

code to detect tab closing event:

window.addEventListener('beforeunload', function (e) {
            e.preventDefault(); 
            e.returnValue = '';
            ... execute server code
        });

The event is not detected.