Having a nightmare trying to get a Construct2 HTML export to work as a Facebook app. The examples on Scirra.com seem to be out of date.
Finally got the Facebook app to work. It seems you can’t do them as websites anymore, you have to do a canvas. Plus it has to be hosted on a secure server (HTTPS). The only other wrinkle is that to get it visible in the Game arcade it has to be assessed before it goes live. That means you’ll need automatic and permissions to post at a minimum plus lots of screen shots of you testing this. If I get a chance I’ll write a tutorial with screen shots and add a link to it.