Display a warning when leaving the site, not just the page

Question

This sounded like something almost impossible to do when it was presented to me. I know you can display a dialog box to confirm when leaving a web page. But is it possible t

Answer 1

You can do that if you design your site as a one page web app.
It means, a single page is loaded, then other contents are loaded dynamically using ajax.

In that case the onbeforeunload is triggered when the user leave the page/site.