Flash Pro CC
Tween.duration
Duration of a tween span that is equal to number of frames in a tween.
var tweenObj = fl.getDocumentDOM().getTimeline().layers[0].frames[0].tweenObj;
if( tweenObj.tweenType == "shape") {
for(var i = 1; i < tweenObj.duration; i++) {
var shape = tweenObj.getShape(i); ///// code to perform some operation on returned shape } }