The original box2d-js library is hosted on sourceforge. It seems to be currently unmaintained and uses the HTML5 Canvas element for display.

This fork has the following changes over the original:

• Spring Joint (simple version, suitable for simulation of soft bodies)

• Removed dependency on prototype.js
• Simple optimisations to core library
• Avoid frequent instantiations of b2Vec2

• Use of SVGs instead of Canvas

  • Using jquery and jquery.svg
  • only create a shape for the first time, then use transformations
  • if static or sleeping then don't redraw

• throttling of step size and inter-frame delays, to achieve a target FPS.

• a new demo scene called drop to show off spring-joints.