JS监听滚动和id自动定位滚动

var scroll = document.documentElement.scrollTop || document.body.scrollTop; //获取屏幕距离顶部的距离

init:function(){
  doc.addEventListener("scroll",function(){ // 实时监听，如果是ios需要做300ms延迟，否则点击索引的时候，对象距离顶部的高度不够，会出现闪动的效果，体验感不佳
    if(!noScroll){
      var appealDo = vm.$el.querySelector("#appealDo").offsetTop- 45; //获取#appealDo距离顶部的距离
      var appealComm = vm.$el.querySelector("#appealComm").offsetTop- 45; //获取#appealComm距离顶部的距离
      var scrollTop = doc.body.scrollTop || doc.documentElement.scrollTop; //获取屏幕距离顶部的距离
      if(scrollTop <= appealDo){
        vm.activeIdx = 0; // activeIdx 是表示高亮，用作顶栏菜单
      }else if(scrollTop > appealDo && scrollTop <= appealComm){
        vm.activeIdx = 1;
      }else if(scrollTop > appealComm){
        vm.activeIdx = 2;
      }
    }
    noScroll = false;
  });
},

toggleTypes:function(idx){
  noScroll = true;
  if (vm.activeIdx != idx) {
    if (idx === 0) {
      doc.body.scrollTop = 0;
      doc.documentElement.scrollTop = 0;
    }else if(idx === 1){
      vm.$nextTick(function(){
        doTop = vm.$el.querySelector("#appealDo").offsetTop - 45;
        doc.body.scrollTop = doTop;
        doc.documentElement.scrollTop = doTop;
      });
    }else{
      vm.$nextTick(function(){
        doTop = vm.$el.querySelector("#appealComm").offsetTop - 45;
        doc.body.scrollTop = doTop;
        doc.documentElement.scrollTop = doTop;
      });
    }
    vm.activeIdx = idx;
  }
},

mounted() {
  window.addEventListener('scroll', this.menu)
},
methods: {
  menu() {
    this.scroll = document.documentElement.scrollTop || document.body.scrollTop;
    var opacity = this.scroll / 44;
    if (opacity <= 1) {
      this.$nextTick(() => {
        this.opacity = opacity
      });
    } else {
      this.opacity = 1
    }

  }
 }