scrollbar reset

heres my existing code : were do i add it, to make the scrollposition = 0

scrolling = function () {

    var scrollHeight:Number = scrollTrack1._height;

    var contentHeight:Number = term2._height;

    var scrollFace1Height:Number = scrollFace1._height;

    var maskHeight:Number = maskedView1._height;

    var initPosition:Number = scrollFace1._y=scrollTrack1._y;

    var initContentPos:Number = term2._y;

    var finalContentPos:Number = maskHeight-contentHeight+initContentPos;

    var left:Number = scrollTrack1._x;

    var top:Number = scrollTrack1._y;

    var right:Number = scrollTrack1._x;

    var bottom:Number = scrollTrack1._height-scrollFace1Height+scrollTrack1._y;

    var dy:Number = 0;

    var speed:Number = 95;

    var moveVal:Number = (contentHeight-maskHeight)/(scrollHeight-scrollFace1Height);

    scrollFace1.onPress = function() {

        var currPos:Number = this._y;

        startDrag(this, false, left, top, right, bottom);

        this.onMouseMove = function() {

            dy = Math.abs(initPosition-this._y);

            term2._y = Math.round(dy*-1*moveVal+initContentPos);

        };

    };

    scrollFace1.onMouseUp = function() {

        stopDrag();

        delete this.onMouseMove;

    };

    btnUp1.onPress = function() {

        this.onEnterFrame = function() {

            if (term2._y+speed<maskedView1._y) {

                if (scrollFace1._y<=top) {

                    scrollFace1._y = top;

                } else {

                    scrollFace1._y -= speed/moveVal;

                }

                term2._y += speed;

            } else {

                scrollFace1._y = top;

                term2._y = maskedView1._y;

                delete this.onEnterFrame;

            }

        };

    };

    btnUp1.onDragOut = function() {

        delete this.onEnterFrame;

    };

    btnUp1.onRelease = function() {

        delete this.onEnterFrame;

    };

    btnDown1.onPress = function() {

        this.onEnterFrame = function() {

            if (term2._y-speed>finalContentPos) {

                if (scrollFace1._y>=bottom) {

                    scrollFace1._y = bottom;

                } else {

                    scrollFace1._y += speed/moveVal;

                }

                term2._y -= speed;

            } else {

                scrollFace1._y = bottom;

                term2._y = finalContentPos;

                delete this.onEnterFrame;

            }

        };

    };

    btnDown1.onRelease = function() {

        delete this.onEnterFrame;

    };

    btnDown1.onDragOut = function() {

        delete this.onEnterFrame;

    };

    if (contentHeight<maskHeight) {

        scrollFace1._visible = false;

        btnUp1.enabled = false;

        btnDown1.enabled = false;

    } else {

        scrollFace1._visible = true;

        btnUp1.enabled = true;

        btnDown1.enabled = true;

    }

};

scrolling();