I ported box2d-lite from C to plain JavaScript. But I've noticed some quirks in the simulation and suspect they're limits based on the scope of Mr. Catto's original code. Although they're just as likely mistakes in my port. I appreciate any input and constructive criticism.

Box2D-LiteJS @ https://github.com/SlowHadoken/Box2D-LiteJS

I made a single file in the test folder that you can just copy and paste into CodePen or JSFiddle. I also put a demo @ https://codepen.io/Daboo/pen/RwNrXbL

I apologize for the vector and matrix math. JavaScript doesn't support overloading operators so I just used static functions.