// ¹ÏÀɨϥΠCtrl + WheelMouse
function imgzoom(o) {
  if (event.ctrlKey) {
    var zoom=parseInt(o.style.zoom,10) || 100;
    zoom-=event.wheelDelta/12;
    if (zoom>0) {
      o.style.zoom=zoom+'%';
    }
    return false;
  } else {
    return true;
  }
}