[Tricks] 移动端弹出层

滚动弹出层时，禁止底部body滚动

  // .vue file
  ...
  watch: {
    isShowPopup (show) {
      if (show) {
        const scrollY = window.scrollY
        document.body.style.position = 'fixed'
        document.body.style.top = `${scrollY}px`
        document.body.curScrollTop = `${scrollY}`
      } else {
        const scrollY = document.body.curScrollTop
        document.body.style.position = ''
        document.body.style.top = ''
        window.scrollTo(0, scrollY)
      }
  },
  ...