Scrollbar question

how can you animate the scroll bar? for example i want to have it to where if i click on link the scroll bar+ text fade in… but when ever i try to do it via motion tween the scroll bar doesnt work… this site has a good example of what i would like click on the links and see how the text+scroll bar is able to be animated(fade in/out), how do i do this? :smiley: