.progress()

Gets or sets the tween's progress which is a value between 0 and 1 indicating the position of the virtual playhead (excluding repeats) where 0 is at the beginning, 0.5 is halfway complete, and 1 is complete. If the tween has a non-zero repeat defined, progress andtotalProgress will be different because progress doesn't include any repeats or repeatDelays whereas totalProgress does. For example, if a TweenMax instance is set to repeat once, at the end of the first cycle totalProgress would only be 0.5 whereasprogress would be 1. If you watched both properties over the course of the entire animation, you'd see progress go from 0 to 1 twice (once for each cycle) in the same time it takes the totalProgress to go from 0 to 1 once.

This method serves as both a getter and setter. Omitting the parameter returns the current value (getter), whereas defining the parameter sets the value (setter) and returns the instance itself for easier chaining, like myTween.progress(0.5).play();

var progress = myTween.progress(); //gets current progress
myTween.progress( 0.25 ); //sets progress to one quarter finished