1.新建permission.js文件

import router from './router'
router.beforeEach((to,from,next)=>{
    let position = window.scrollY; //记录离开页面的位置 
    if (position == null) position = 0;
    sessionStorage.setItem(from.name,window.scrollY);
    next() 
});

router.afterEach((to, from) => {
    let scrollY = sessionStorage.getItem(to.name);
    if(scrollY){
        window.scrollTo(0,scrollY);//定位页面上次滚动的位置
    }else{
        window.scrollTo(0,0);
    }
  });

2.在mian.js里引入该文件

import './permission';