How do you convert a color image to black/white using Javascript?

Question

How do you convert a color image to black/white using only Javascript?

AND, also make it cross compatible in most browsers because I hear Internet E

Answer 1

Canvas is indeed the best client-side solution to this problem, and I just wanted to point out that, for IE, you can actually use the google exCanvas project which translate canvas commands into the proprietary Microsoft XML-based vector language, VML.

http://excanvas.sourceforge.net/