This piece of code creates a Rich Text Editor ("RTE") from an IFRAME element. Yes, I know, there are tens of such scripts, and most of them are probably more sophisticated than mine, but my script's purpose is to provide enough basic functionality while having the smallest footprint possible.
The code relays on the fantastic jQuery library, which is incorporated today into most Platforms anyway, so no code overhead there...
Apart from jQuery, you'll need to include one JS file and one CSS file and you're done.
I recommend using the minified/packed versions in conjuction with GZIP compression, to get the best results!