[EDIT: Sorry to those who already answered -- in my sleep-deprived state, I forgot that this particular situation is a YouTube movie, not the JW FLV player. I can see th
Flash movies are pretty much black boxes as far as javascript is concerned. If the SWF you're using wasn't written to interact with javascript then you're probably out of luck.
You'll either need to figure out what javascript methods the movie you're using exposes (hopefully it has documentation), find another one that does provide javascript interaction, or write your own SWF to handle it.