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.

Answer 2

One (slightly hacky) way to do it is replace and links that lead away from your site with an AJAX call to the server-side, indicating the user is leaving, then use that same javascript block to take the user to the external site they've requested.

Of course this won't work if the user simply closes the browser window or types in a new URL.

To get around that, you'd potentially need to use Javascript's setTimeout() on the page, making an AJAX call every few seconds (depending on how quickly you want to know if the user has left).