Really nice demo.
But there's one semi-unrelated thing I noticed (disclaimer: yeah, I don't like Flash either, but): This demo, with a handful of animated bezier curves drove one CPU to 40% (using Chrome on a Mac). And this is something that I repeatedly encountered with graphics rendering done in Javascript. The whole "less flash"="less cpu-usage with animation"-thing might be a little premature.
The only problem I see with this approach is the Javascript-interpreter seeing through your pointer system and holding a reference to the object pointed to - which defeats the purpose of creating a possibility to segfault...
Sorry, but the only thing more painful to read and edit than pure regular expression syntax is string-escaped regular expression syntax. I still cringe when I remember writing this in C and Java.