Best way to detect when a user leaves a web page?

Question

What is the best way to detect if a user leaves a web page?

The onunload JavaScript event doesn\'t work every time (the HTTP request takes longer than t

Answer 1

I know this question has been answered, but in case you only want something to trigger when the actual BROWSER is closed, and not just when a pageload occurs, you can use this code:

window.onbeforeunload = function (e) {
        if ((window.event.clientY < 0)) {
            //window.localStorage.clear();
            //alert("Y coords: " + window.event.clientY)
        }
};

In my example, I am clearing local storage and alerting the user with the mouses y coords, only when the browser is closed, this will be ignored on all page loads from within the program.