If you have turned off Flash or no Flash available (e.g. on iPhone), the original Web-site says:
You need Flash to view this content.
Box2DFlash is an actionscript library, do you really think you could avoid Flash on the website?
Actually, yes. It is possible!
The button on the right-hand side loads the original Flash version of the demo (and of course only works if you have a Flash-enabled browser).
Demo Instructions: Click and drag to manipulate items in the 2D world. To use the keys to step to another demo, you have to focus (click) into the corresponding demo version (Jangaroo left, Flash right) first.