One of the best things to happen in Facebook development lately was to enable iframe application tabs. This was widely welcomed by developers. However many blog posts wrongly assumed there was a 800 pixel limit on the tab height. Behold, here is the 5000 pixel tab.
Facebook developing is pretty much trial and error. Documentation has lately been improving a lot. Still there are lot of surprises. Especially with FBJS. Recently I got stuck with a problem of Ajax requests sometimes silently failing. Developer forums and Stack Overflow had the same problem but no answer.
First user clicks a submit button in application tab. Code will then show dialog requesting for extra permissions.
After giving the permissions code should submit form data to server. I also wanted to to receive the uid of current user. Hence the parameter ajax.requireLogin is set to true.