判断鼠标滑轮滚动事件

windowAddMouseWheel() {
  let that = this
  let scrollFunc = function (e) {
    e = e || window.event
    if (e.wheelDelta) {  //判断浏览器IE，谷歌滑轮事件
      if (e.wheelDelta !== 0) { //当滑轮滚动时
        that.visible = false
      }
    } else if (e.detail) {  //Firefox滑轮事件
      if (e.detail !== 0) { //当滑轮滚动时
        that.visible = false
      }
    }
  }
  //给页面绑定滑轮滚动事件
  if (document.addEventListener) {
    document.addEventListener('DOMMouseScroll', scrollFunc, false)
  }
  //滚动滑轮触发scrollFunc方法
  window.onmousewheel = document.onmousewheel = scrollFunc
},