Ability for users to choose htmlarea or normal text box

I have lots of users who cannot use htmlarea, due to browser issues, etc. (Some users even use WebTV!), and who cannot upgrade for various (usually monetary) reasons (aging computers, don't own their own computer, etc.). The site(s) in question aren't the sort where it's appropriate to tell people "If you can't upgrade, you are out of luck".

The majority of my users _can_ use it just fine, and I'd love to make it available for those who can use it without trouble.

It would be great if there were a way that users could enable/disable it depending on whether they can use it, (or want to use it). It would also be great if it did some browser detection to automatically disable it for browsers where it can't work. (I normally use a mac browser called Camino, which is Gecko-based, but which doesn't support htmlarea... I often end up having to switch browsers when I run across a site that uses htmlareas)

Right now, because I have to worry about the least common denominator of capability, I can't use htmlarea at all on the sites I maintain.

Coyote