What is CAAT ?

It is a

JavaScript based

(there can be more than one executing instance per html document)

scene-graph manager
(CAAT actors are entities which have state and may contain other actors).

CAAT stands for Canvas Advanced Animation Tookit.

The rendering engine is not only focused on Canvas actually. WebGL and CSS can be selected too.

CAAT it is a complete gaming framework, featuring on-screen entities, custom matrix stack, game loop hooks, scenes, scene transition, affine transformations, pixel perfect on-screen entity identification, complex paths, behaviors, seamless box2d integration, multitouch, etc.