query string

[Stevan]

i`m kind of a newbi in Scripting in general. I need to dynamicaly load a another element (swf or picture) in the index HTML using a query string. kind of like this http://balhblahblah.com/movie.swf?pic=a.gif

any ideea on how i can do this in a very simple way? (as i said before i am a newbi and i`m experienceing trouble with this at the office)
My job depends on your help! :D (just kidding, but help would be nice)

Thank you...
Steven