I great site to compare what different browsers support is http://caniuse.com http://caniuse.com . For example, you can see that IE9 and Firefox 3.5 are quite c

I great site to compare what different browsers support is http://caniuse.com http://caniuse.com . For example, you can see that IE9 and Firefox 3.5 are quite closely matched here: http://caniuse.com/#compare=y&b1=ie+9&b2=firefox+3.5 http://caniuse.com/#compare=y&b1=ie+9&b2=firefox+3.5 As a web developer (and Firefox user), I believe that IE9 is miles better that any previous version of IE but I still think Microsoft have a lot of catching up to do. Hopefully IE10 will lessen the gap even more.