滚动页面分割图像按钮也向下滚动

我创建了div Over Image按钮css样式的位置是绝对的当我滚动页面时，div也向下滚动我如何修复图像转换按钮

#DamageDiv {
background-color:red;
position:absolute;
z-index:1000;/* heighest z-index show on top */

}

function DrawImage(e) {
        var evt  = e || window.event; // compliant with ie6 
        var posX = evt.clientX;
        var posY = evt.clientY;
        var iDiv = document.createElement('div');
        iDiv.id = DamageType;
        iDiv.style.top = posY + "px";
        iDiv.style.left = posX + "px";
        iDiv.style.width = "20px";
        iDiv.style.height = "20px";
        document.getElementsByTagName('body')[0].appendChild(iDiv);
    }