How do I get window onunload event trigger to work in Chrome v73.x?

Question

It appears that with the latest release of Chrome (Version 73.0.3683.103 (Official Build) (64-bit)), window onunload event handler isn't being called.

In the latest version of Chrome, my onunload anonymous function seems unreachable.

I'm following MDN Web Docs (https://developer.mozilla.org/en-US/docs/Web/API/WindowEventHandlers/onunload).

window.addEventListener('unload', function (e) {
  console.log('It worked');
  debugger;
});

When I run developer tools in each browser, my snippet of code in Chrome Version 66.0.3359.117, and in Firefox 66.x pauses on the debugger breakpoint as expected when refreshing the window or clicking the back/forward button. Exiting out of the tab, or completely closing the browser works as expected.

https://codepen.io/anon/pen/jRxJxJ

It may have to do with the iframe. Putting that code into a *top-level* ` — CertainPerformance, Apr 20 '19 at 00:04
it does the `console.log` but doesn't stop at `debugger` - I'm actually surprised any browser would stop at `debugger` on unload!! — Jaromanda X, Apr 20 '19 at 01:25
@CertainPerformance, after I put the code in the top level, or just directly into the console, it works when I close the browser tab. The back, forward, and refresh buttons still don't seem to be reaching the unload hook for me. — Kyle Dalan, Apr 22 '19 at 16:58

score 2 · Accepted Answer · answered Apr 20 '19 at 00:06

2

Instead unload, use window.onbeforeunload for Chrome and it will work fine!

window.onbeforeunload = function (e) {
  console.log('It worked');
  debugger;
};

Here is the event triggered in Chrome when I close the window.

answered Apr 20 '19 at 00:06

Jonathan Gagne

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OP's original code works just as well when typed into the console like you did, though. – CertainPerformance Apr 20 '19 at 00:12
What version? It's working for me on Chrome 73.0.3683.86 – CertainPerformance Apr 20 '19 at 00:13
Version 73.0.3683.103 (Official Build) (64-bit) – Jonathan Gagne Apr 20 '19 at 00:14
There are some actions which are not working in chrome, inside of the unload event. Alert or confirm boxes are such things. https://stackoverflow.com/a/9325742/8089090 – Jonathan Gagne Apr 20 '19 at 00:18
I updated to 73.0.3683.103 and OP's original code still works: https://i.stack.imgur.com/oSHaG.png – CertainPerformance Apr 20 '19 at 00:26
Interesting... Sorry I cannot help you on that one. – Jonathan Gagne Apr 20 '19 at 00:30
@JonathanGagne In my application, for the last few years, the unload hook was catching refresh/forward/back/close events. I still believe something changed within Chrome (Firefox still works as expected). Changing my hook from unload to onbeforeunload does technically fix my issue, much appreciated. I'm still left scratching my head on what changed within Chrome. – Kyle Dalan Apr 22 '19 at 17:19

How do I get window onunload event trigger to work in Chrome v73.x?

1 Answers1