Though I've never read any Batman comics.
Watched Batman (the film, Tim Burton) last night
IIRC, the comics also pointed the Joker as the man who murdered Bruce's parents, but, like Superman, the background/concept of Batman has been rewritten several times..
Then again, been years since I read the comics, and I always prefered Spiderman.. The latest movies have taken most of the good points of the comics and IMHO didn't damage a thing. (Biggest change is the way SPidey handles his web, in the comic he makes it with chemistry and some gadget.. In the movie it's built in so to say)