Content slide. acs help

1

hi
im trying to modify a .fla flife that i found
and it consist in move the background based on the mouse movement
this sample i got is only moving at _x position (horizontal)
and i want to make it only for _y (vertical)
i try to modify the script but im not so good on that
can anyone help me modifing it?

here it is:

//This is a fullscreen demo. Minor changes will need to be made if using the code in an embedded swf with confines < the stage
fscommand("fullscreen", "true");
Stage.scaleMode = "noScale";
//Center the stage elements
var myListener:Object = new Object();
myListener.onResize = function() {
    updateLocations();
};
Stage.addListener(myListener);
updateLocations = function () {
    // Values of the initial .swf width and height
    initialWidth = 800;
    initialHeight = 450;
    // Get the current stage width and height
    currentWidth = Stage.width;
    currentHeight = Stage.height;
    // Get the content width
    contentWidth = contentClip._width;
    // Position content vertically
    contentClip._y = Math.round((initialHeight/2)-(contentClip._height/2));
    // Center the content if the content width is less than currentWidth
    if (contentClip._width<currentWidth) {
        newX = Math.round(initialWidth/2-contentClip._width/2);
    } else {
        positionContent();
        newX = Math.round(initialWidth/2-contentClip._width/2);
    }
};
updateLocations();


//Number of buffer pixels to add on each side of the content
buffer = 0;
//Scroll the content relative to the mouse
this.onMouseMove = function() {
    //Only fire if mouse is over the content area
    if ((this._xmouse>Math.floor((initialWidth-currentWidth)/2)) && (this._xmouse<Math.floor(initialWidth+2*((currentWidth-initialWidth)/2))) && (this._ymouse>contentClip._y) && (this._ymouse<(contentClip._y+contentClip._height))) {
        //Make sure the content width is larger than the currentWidth
        if (contentClip._width>currentWidth) {
            positionContent();
        }
    }
};
positionContent = function () {
    // Percent of mouse position on content
    mousePercent = (this._xmouse+(currentWidth-initialWidth)/2)/currentWidth;
    // Total available movement of the content minus screen width
    availMovement = contentClip._width-currentWidth+buffer*2;
    newX = Math.floor(-mousePercent*availMovement)-(currentWidth-initialWidth)/2+(buffer*2)/2;
};
//Set the initial position to the left side of the screen if content width is more than currentWidth, else center the content
if (contentClip._width>currentWidth) {
    newX = Math.floor((initialWidth-currentWidth)/2)+buffer;
} else {
    //Center the content
    newX = Math.floor(initialWidth/2-contentClip._width/2);
}
//The following 2 functions can be rewritten to utilize the Braingiants Bounce function for improved recycling (it is presented as is for clarity of the actual movement)
holder = contentClip._x;
easeContent = function () {
    // Don't fire if the destination position is met
    if (newX<>contentClip._x) {
        destx = newX;
        posx = holder;
        velx = (destx-posx)/4;
        holder += velx;
        contentClip._x = Math.round(holder);
    }
};
contentClip.onEnterFrame = function() {
    easeContent();
};
updateLocations();
stop();

i let the fla attached
thanks