Rich text usually equals client side.
To prove the point, does it work in Mozilla or Opera? If yes, it could still be client side and just a freak of nature (I think I've heard folks saying it only works in IE - which proves its client side).
If its client side, then its just a matter of grabbing the JavaScript and HTML.
Mozilla has this capability with Midas. Its client side (you define a tag or two and then toss in a sprinkling of JavaScript and you're good to go). The one I'm using actually works in IE, Moz/Fire, and sort of in Safari (Safari has JavaScript issues).
Not sure by what you mean "server side" since the server really doesn't do anything special other than shoot the data to the browser and retrieve it (to retrieve "rich text" is just an excercise in retrieving HTML instead of just plain text).
