[removed] and [removed] is not working in Firefox , Safari , Opera?

Question

In my chat application I need to get confirmation from user , when my application closes.

So I used the window.onbeforeunload for confirmation alert and

Answer 1

Unfortunately, the methods you are using are unsupported in those browsers. To support my answer (this unsupportive behaviour) I have given links below.

onbeforeunload and onunload not working in opera... to support this

onbeforeunload in Opera
http://www.zachleat.com/web/dont-let-the-door-hit-you-onunload-and-onbeforeunload/

Though the onunload event doesn't work completely, you can use onunload to show a warning if a user clicks a link to navigate away from a page with an unsaved form.

onunload not working in safari... to support this

https://www.webkit.org/blog/516/webkit-page-cache-ii-the-unload-event/

You could rather try using the pagehide event in the safari browser in lieu of onunload.

onunload not working in firefox... to support this

https://bugzilla.mozilla.org/show_bug.cgi?id=681636

They are yet to come up with a solution in FF too

Wish you good luck cheers.