How to stop mc scrolling off stage

[wownflutter]

I have an mc being scrolled under a mask by forward and backward buttons.

But, I can't figure out how to get the mc from being able to scroll off stage!

Help!

[Flash Gordon]

if (_mc > 0 && _mc < Stage.width) {
// scroll
}

[wownflutter]

Where do I put this code?

Is it part of a button script? or just put into a frame... or?

Thanks!

[Flash Gordon]

depends on how you are moving it, but I'm guess on button.

[wownflutter]

How can you apply that to this mc button:

on(press){
_root.panel_mc.tween("_x", _root.panel_mc._x-780, 1.1,"easeOutExpo", 0);
}