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
 }

 }
 }