ANIMATION "HALF PIE" ELECTIONS

ANIMATION "HALF PIE" ELECTIONS

I need to make an animation of a "half pie " in js

Here you can see as I did in Flash:
http://www.elperiodico.com/es/elecciones-28n/

And here in JS:
http://especiales.elperiodico.com/LABS/ELEC2011B/html/emi-basic2.htm

But I can not create the animation from left to right as I did with flash.

Some kind soul can help me:)

Thank you very much
Agustí from Barcelona