Controlling movieclip position

programming flash
1

Hey, I’m building a gallery for my new site and scroll the thumbnails inside a movieclip controlled by up/down buttons. I’ve got the scrolligg to work fine but now I need it to stop when it reaches a certain point.

Here’s an example of what I’m working on. As you’ll see, if you keep hovering on the up or down buttons the thumbnails keep moving and disappear.

I’m using the following code:

gallery_up_btn.onRollOver = function() {
    gallery.onEnterFrame = function() {
        this._y -= 4;
    };
};

gallery_up_btn.onRollOut = function() {
    delete gallery.onEnterFrame;
};

gallery_down_btn.onRollOver = function() {
    gallery.onEnterFrame = function() {
        this._y += 4;
    };
};

gallery_down_btn.onRollOut = function() {
    delete gallery.onEnterFrame;
};

Any ideas?

Al