I just stumbled on a cool site – html5readiness.com. The site displays a break down of browser support for HTML5 and CSS3 (Canvas, SVG, GeoLocation, Transforms, Border Radius, etc). The browsers included for 2010 are IE 7, IE 8, IE 9, FireFox 3.5, FireFox 3.7, Opera 10.50, Safari 4, and Chrome 4.
I wasn’t surprised to find that Safari and Chrome have the most HTML5 and CSS3 support (since both use the webkit engine). Firefox support for HTML5 and CSS3 is not far behind Safari and Chrome.
I was not surprised to find that Internet Explorer lags far behind (although IE 9 adds support for SVG, Video, SVG as Background, Media Queries).
I was very surprised to find that HTML5 and CSS3 support in Opera 10.50 rivals that of FireFox.
Anyway, if you ever need to know what is supported by each browser, take a look at html5readiness.com.
P.S. I wonder why Safari and Opera aren’t used as much as Firefox, Chrome and IE. Safari can be used with a Mac or PC, but appears to be used primarily by Mac users. Chrome has been around since 2008 and already has 5 times as many users as Safari (see browser stats).