Image Pan positioning

programming flash
1

Hello, I Found this website when I am looking for a Image Pan positioning solution.
eg:http://www.sephiroth.it/tutorials/flashPHP/scrollRect/index.php
Following code is what I found here coded by Krilnon.
Looks like I need to use xy instead of x, anyone know how to archive that?
Many thanks!:ne:

function constrainedMove(target:MovieClip, speed:Number, dir:Number) {
    var mousePercent:Number = _ymouse/Stage.height;
     var mSpeed:Number;
     if (dir == 1) {
        mSpeed = 1-mousePercent;
    } else {
    mSpeed = mousePercent;
 }
target.destY = Math.round(-((target._height-Stage.height)*mSpeed));
target.onEnterFrame = function() {
     if (target._y == target.destY) {
     delete target.onEnterFrame;
} else {
     target._y += Math.ceil((target.destY-target._y)*(speed/100));
}
};
}