unitbezier
Unit bezier interpolation function: a port to JavaScript from Webkit:
http://svn.webkit.org/repository/webkit/trunk/Source/WebCore/platform/graphics/UnitBezier.h
api
new UnitBezier(p1x, p1y, p2x, p2y)
Initialize a new bezier curve given the points
bezier.sampleCurveX(t)
bezier.sampleCurveY(t)
bezier.sampleCurveDerivativeX(t)
bezier.solveCurveX(t)
bezier.solve(x, epsilon)