Google Chrome and Konqueror 4.8 do not support MathML natively;
Safari 5.1 reportedly does. However, I sometimes find Chrome to
work better than Firefox on interactive sites that serve complex
web forms such as online banks, stores, and LinkedIn. I routinely
use both Firefox and Chrome. Google Chrome requires the "Math Anywhere" extension.
MathML may be displayed in Internet Explorer, but requires the
plugin. (Not tested.)