I need a 2D bone engine for JavaScript

I'm looking for a way to define a Bone animation system, I need a basic one, since my objective is to apply it for inverse kinematics, much like Flash supports.

The desirable feature is that: I can set bones (as position in 2D, defined by 2 dots) each having an ID. So I 开发者_StackOverflowcan make an animation based on frames, ie:

['l_leg', [10, 0],[ 13,30 ] ] ['r_leg', [30, 0 ], [13, 30] ] //Frame 1 (standing)
['l_leg', [10, 0],[ 13,30 ] ] ['r_leg', [35, 30], [13, 30] ] //Frame 2 (lifting right leg)
...

I'm confident that defining Joints ain't necessary.

The lib may be lib in Ruby, since I can port it to JS, but if in JS already is better :)

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UPDATE: deprecated for a long time now.

I am developing my own: http://github.com/flockonus/javascriptinmotion

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See Wikipedia: Express Animator.

1st result for Google: javascript skeletal.