FBML + FBJS == XFBML?

Question

I am trying to understand what exactly is the difference between fbml and xfbml! Is XFBML same as FBML combined with java script?

Answer 1

FBML is a facebook's propriety mark-up language, and originally all app views were static rendered in just FBML. Developers wanted to make their facebook app views more dynamic though, but they couldn't use javscript in FBML, so facebook created FBJS to allow developers to make their pages dynamic.

Later, they added support for iframe views, which originally were just HTML. Finally, they added support for embedding FBML tags in a regular document using XFBML. So using your analogy above, it's more like HTML + FBML = XFBML.

In any case, both static FBML and FBJS are both being deprecated any will eventually be removed entirely, so it would be a bad idea to use either of them. XFBML can still be rendered using the Facebook Javascript API, so it's not as bad an idea to use XFBML, but still not the best idea. Regular HTMl and javascript combined with the Facebook Javascript API can do everything XFBML can do, and it can do it more cleanly.

Answer 2

No.

FBML is the old markup language which was proxied through Facebook servers and re-written into HTML that was rendered as your app. FBJS is a subset of JS that you could use in FBML pages. It was also proxied and rewritten by the facebook servers. FBML has been deprecated for some time.

XFBML is code that is served directly from your server to end users in an iframe, then processed client-side by Facebook-provided javascript to generate facebook-specific UI elements. It reduces page load time and the CPU load on Facebook's servers because they don't have to proxy and process everything.