Auto scroller _x position?

I got this tutorial for an auto scroller…works fine but where the foofoo did she get the _x value from in frame1??? I can’t understand them or the explanations joined.

So following Lunatic advice I’m trying to redo the tutorial I had. The scroll starts and stops at the right position but only scroll one way and also with the mouse off the frame (wanted it to do it so that it scrolls only when the mouse is actualy over the scrolling movie). This is also my first real try in actionscript so it had to hapen…I’m stuck.

Fla is atttached for any AS guru (I can hear Scotty’s brain cells buzzing:ear: )