The demo seems to be based on something named processing.js, which is, apparently, a port of Processing (i.e., a Java-like language for software artists) to JavaScript.
Characterising Firefox 3.5, Safari 4, etc. 'cutting edge' does only does justice to the crappy family of IE broswers that do not support modern web technologies because Microsoft chooses to for strategic reasons. Indeed, FF 3.5, Firefox 3.5.x, Opera 10 are the _stable_ versions of the browsers and one should call them 'modern' rather than 'cutting edge' as this often gives the impression that they are not stable or common.
'Modern browsers' makes the point that these browsers are what is the current state of the art and IE with its lousy support for modern web technologies is not.
Thanks!
Firefox 3.5 and Safari 4 are both recent versions, and the previous stable versions didn't support enough HTML5 features for this demo to work. And some systems (such as Ubuntu Linux) still haven't integrated Firefox 3.5 into their mainstream distributions.
I'm all for encouraging everybody and their dog to use Firefox (or Chrome, or Safari, or, indeed, anything but IE), but passing off the latest innovations as the average in the non-Microsoft world would just set them up for disappointment if everything's not entirely ready.
The week I spent playing with Processing was the most fun I'd had with a programming language since learning BASIC on my old Amstrad...but the fact that it output to Java applets was a real downer. I will definitely have to check out this processing.js deal.