Getting a new media location via JS?

I have created a FLV player for a client and it does everything they need (Pos Bar, Volume Bar, Full Screen, Etc…) Now the only thing left to do is they want to be able to call the playVideo(file.flv) function via JavaScript. I don’t know if that is possible and if it is not, how else would I go about being able to update the file var in the swf from an outside source (PHP/JS)?

Thanks,
Flash-matic :dog: