鼠标滚轮缩放图片

function ZoomImg(o)
        {
            var zoom = parseInt(o.style.zoom, 10) || 100;
            zoom += event.wheelDelta / 12;
            if(zoom > 0)
                o.style.zoom = zoom + '%';
            return false;
        }

 <img src="images/img.gif" onmousewheel="return ZoomImg(this)"  width="200" height="200">