JavaScript Physics Libraries

In my research for a JavaScript physics library, I've found the following:

• Box2DJS - This is the oldest one. It is created by using an ActionScript to JavaScript converter to convert Box2DFlashAS3 1.4.3.1, which is a port of the original Box2D C++ library.
• Thinkpixellab's version of Box2DJS - They have run Box2DJS (above) through Google's Closure Compiler and claimed to have also fixed many bugs.
• box2dweb - Similar to Box2DJS, this is created by coverting Box2DFlash 2.1a to JavaScript. You can find the API reference here.
• Toxiclibs.js - This library is very different than Box2D based libraries. First of all, it supports 3D and 2D simulation. It appears to be primarily for particle physics systems (so I don't think you get physics simulation for a object graph of polygons/shapes). However, it does do particle-like systems quite well (think flocking boids).