Just to preemptively address a criticism: yes, this does frame-by-frame animation in JavaScript, eschewing CSS animations. There are tricks you can use (similar to what iScroll does or did) that can leverage CSS animation, but it's likely that these won't be necessary or worth it.
The reason for this is that to truly solve animation you need to address continuous touch gestures that seamlessly transition into and out of animations (i.e. flick something, catch it with your finger mid-animation, zoom it while rotating it, then let go and have it animate out). The only way to do this is to use a programming language that can respond to events. Said another way, you should never think of animations discretely (i.e. "slide in from left") if you're thinking about building touch-based app. It won't feel natural.
My old employer has a great video about this. Detailed discussion starts here (there are two speakers that talk about it): http://youtu.be/OiY1cheLpmI?t=25m29s