Detect browser or tab closing
Solution 1:
If I get you correctly, you want to know when a tab/window is effectively closed. Well, AFAIK the only way in Javascript
to detect that kind of stuffs are onunload
& onbeforeunload
events.
Unfortunately (or fortunately?), those events are also fired when you leave a site over a link
or your browsers back button. So this is the best answer I can give, I don't think you can natively detect a pure close
in Javascript. Correct me if I'm wrong here.
Solution 2:
From MDN Documentation
For some reasons, Webkit-based browsers don't follow the spec for the dialog box. An almost cross-working example would be close from the below example.
window.addEventListener("beforeunload", function (e) {
var confirmationMessage = "\o/";
(e || window.event).returnValue = confirmationMessage; //Gecko + IE
return confirmationMessage; //Webkit, Safari, Chrome
});
This example for handling all browsers.