js监听纵向滚动条位置

    // 监听页面滚动
    handleScroll () {
      let scrollTop = window.pageYOffset || document.documentElement.scrollTop || document.body.scrollTop
      if (scrollTop > document.body.clientHeight/2) {
        this.showBackTop = true
      } else {
        this.showBackTop = false
      }
    },
    // 活到顶部按钮
    backTop () {
      document.body.scrollTop = 0
      document.documentElement.scrollTop = 0
      // window.pageYOffset = 0    微信浏览器里不支持
    }

标签：body,pageYOffset,documentElement,js,滚动条,window,scrollTop,document,监听
来源： https://blog.csdn.net/FUSHENGRUOMENG111/article/details/122621463