addEventListener(Event.ENTER_FRAME, enterFrame);

 

function enterFrame(e:Event):void{

    var distance:Number = Math.round(scrollMC.y-bounds.y);

    var percentage:Number = distance/myMask.height;

    var targetY:Number = ((loader.height-myMask.height)*percentage)+myMask.y;

   if(scrolling == true){

     loader.y = -(targetY);

   }

function enterHandler(e:Event):void{

                                        distance = Math.round(scrollMC.y-bounds.y);

                                        targetWay = loader.height-myMask.height;

                                if(scrolling == true){;

                                                loader.y = -((targetWay/250)*distance);