Lol ... yes .. same SP from ASP Messageboard! I believe you have a "B" and "W" in your name - in fact, I think you directed me to this board! I have been lucky to mainly be doing CSS work, but this switcher (JS still makes my head spin) plays into making the sites I do more accessible, which I think is a good approach ..
I have it here:
No noticeable JS errors, but it does not add the class to the body element.
Regardless, I still can not understand how you write code like this off the top of your head. You definitely showed me solutions more than once.
PS - Note made on cookies - I seem to be in the clear!