Facebook: Pop-in.
What do you do when you have a Facebook app tab (inside an iframe, mind you) that’s externally linkable? Pop-in. Let’s break this down. if (self === top) { This conditional will be true when the browser is not inside an iframe. window.location.href = 'https://www.facebook.com/test/app_1234'; If we are not inside an iframe, then redirect to the following URL.