posted message: About cross-browser compatibility: I like to test my example code on at least the latest Chrome, Safari, Firefox 4, and IE 9. (I should really start testing in Opera as well...)
IE 9 is the version where Microsoft has committed to supporting HTML 5. So IE 9 should be capable of handling everything we do in this course, and we should all be testing our stuff to make sure it works on IE 9.
Older versions of IE... well, Microsoft never made any promises about them supporting HTML 5, so I don't expect most of the techniques in this course to work there. In particular, IE 8 and older don't support (although there are some hacks to add canvas support). So I'm not too sad if my code doesn't work in older versions of IE.