router.beforeEach((to, from, next) => {
点击倒退历史记录 退出
  if(from.path == '/404'){
    window.history.back(-1)
  }
  if (to.path == '/login') {
    sessionStorage.removeItem('boxToken');
    sessionStorage.removeItem('bospower');
  }
  let bospower = sessionStorage.getItem('bospower')
  let boxToken = sessionStorage.getItem('boxToken')
  if (!boxToken && to.path != '/login') {
        next({ path: '/login' })
  } else {
     if(to.path=='/login'){
        next()  
      }
      else if(userDiction['jurisdiction'][bospower].indexOf(to.path)>=0){
        next();
      }
      else {
        next({path:'/404'});
      } 
    }
  
})