JTrackBar水平拖动效果

        oBtnPointer = $c("DIV");
        oOutline.appendChild(oBtnPointer);

        //oBtnPointer.onclick = trackarea_click;
        oBtnPointer.onmousedown = pointer_mousedown;
        //oOutline.onmousemove = oBtnPointer.onmousemove = pointer_mousemove;
        //oBtnPointer.onmouseup    = pointer_mouseup;
        //oBtnPointer.onmouseout = pointer_mouseout;

        oBtnPointer.className = "btnPointer";
        oBtnPointer.style.position = "absolute";

        var w_ = parseInt(getRunStyle(oBtnPointer,"width"));

        var pos_ = JPos.getAbsPos(oTrackArea);
        oBtnPointer.style.left = pos_.x - w_/2 + "px";
        oBtnPointer.style.top = pos_.y + "px";
        oBtnPointer.style.cssText += "left:" + (pos_.x - w_/2) + "px;top:" + pos_.y + "px;";
    }

    /*-----------------------------------------------------*/
    this.createHTrackBar = function(pWidth){
        outlineWidth = pWidth;
        createOutline(pWidth);

        oArrBtnLeft = createArrBtn("LEFT");
        oOutline.appendChild(oArrBtnLeft);

        createHTrackArea();

        oArrBtnRight = createArrBtn("RIGHT");
        oOutline.appendChild(oArrBtnRight);

        createHPointer();
    }
    /*-----------------------------------------------------*/

    this.setPositionBy = function(pPosition){
        position += pPosition;
        self.setPosition(position);
    }

    this.setPosition = function(pPosition){
        position = pPosition;