Chipmunk.js is a port of the Chipmunk library to Javascript. Chipmunk is a rigid body physics library in C designed for 2D games.
It’s not a 1:1 port of the API, more of an OOP-Port. For instance cpSpaceAddShape(space, foo) in Chipmunk is space.addShape(foo) in Chipmunk.js.

Currently most of the API is ported.

Since most of the code is similiar to the original C version there still is a lot of potential (and probably need) for optimizing it for Javascript.

It’s not recommend to use Chipmunk.js yet, since it’s largely untested and unstable (for instance putting components to sleep tends to run into an infinite loop) and still in a very early alpha stage!

Until now it only requires a AMD compatible scriptloader like requireJS or curl.js.

Chipmunk.js is licensed under the terms of the MIT license: http://murphy.mit-license.org/