On a 2010 macbook that runs at 15fps, which is a great step forward in speed for moving 8 sprites. Have you actually tried to animate anything other than a solid body, in just code?
http://www.idleworm.com/how/anm/02w/walk1.shtml is a walk cycle, and as you can see they are animating the control points, so the body smoothly deforms. As far as I'm aware you can control individual control points of an SVG with javascript. Even if you could without a decent interface you couldn't do more than move a ball about.
HTML/JS is shit at animation.
Flash is rubbish, and can be much more efficient, however HTML/JS is 10 times worse.
Ha, +1 point for snarkiness, -10 points for thinking that walk cycle experiment is a comparable example to even average Flash animation work, +9 points hoping for the love of the internet that you were just trying to make a laugh = net worth of nothing.
Flash is dead.