Can I incorporate prototype.js into an FBML facebook application?

we have a lot of existing code in a web application that we want to use in a facebook application. Much of it on the client si开发者_Go百科de depends on prototype.js.

Can I incorporate prototype.js into my FB application without difficulty, and am I going to have to make a choice about iFrame vs FBML early on?

You will need to choose between iFrame or FBML early on; in fact, it's generally the first thing you do. If you go with iFrame, you may use whatever JavaScript library you like. FBML, on the other hand, is very restricted and does not allow it.