Yes/No box in Javascript like this one here in StackOverflow?

Question

I want to know how can I display a confirmation box when the users try to get out of the page, like this one here in StackOverflow when you try to close the "Ask Question" page.

Thanks you in advance.

Answer 1

Actually, all that is necessary is this:

window.onbeforeunload = function(){ return "You should save your stuff."; }

This is also kind of a dupe of this: How to show the "Are you sure you want to navigate away from this page?" when changes committed?