watchScroll() {
  this.$nextTick(() => {
    const el = this.$refs["discussInfoBox"];
    const offsetHeight = el.offsetHeight;
    el.onscroll = () => {
      const scrollTop = el.scrollTop;
      const scrollHeight = el.scrollHeight;
      if (offsetHeight + scrollTop - scrollHeight >= -1) {
        // 需要执行的代码
        console.log("get info ");
      }
    };
  });
},