Change html background from flash

hi does anyone know if its possible to set the background colour of the html page from flash? im making a transparent swf and i want to provide colour swatches that the user can change the background on the movie. i have explored other ways of doing this, but for what i making it makes more sense to have the html background change. ideally i would like it to be a gradient too. i have used a repeating background image in dreamweaver at the moment. is there anyway actionscript can control css?

sorry still a bit of a nube. using cs3 at the mo.

cheers,

cew