This is a port of Box2DFlash 2.1a to JavaScript. We developed an ActionScript 3 -to- JavaScript compiler to generate the code.
There already exists a port to JavaScript called Box2dJs, but it's not up-to-date and you have to import a big amount of JavaScript files in every project, whereas my version is stored in a single file.
The Box2D physics engine was developed by Erin Catto (visit http://www.gphysics.com for further information)
You can read the documentation for Box2dFlash, since nearly everything is organized the same way. http://www.box2dflash.org/docs/2.1a/reference/
The b2DebugDraw takes a canvas-context instead of a Sprite:
var debugDraw = new Box2D.Dynamics.b2DebugDraw;
debugDraw.SetSprite(document.GetElementsByTagName("canvas")[0].getContext("2d"));
Please notice that Box2dWeb is a physics engine. The graphics in the demo are generated by the b2DebugDraw-class, which is only available for debugging purposes. If you want to apply the computed coordinates to real graphics you should use a graphics library such as IvanK developed by Ivan Kuckir. The website of IvanK even contains a Box2dWeb example: http://lib.ivank.net/index.php?p=demos&d=box2D