demo\src\main.js
	import { createApp } from 'vue'
	import App from './App.vue'

	import router from './router'

	//createApp(App).mount('#app')
	const app = createApp(App)
	app.use(router)

	//全局前置守卫
	router.beforeEach((to, from, next) => {
	    console.log("to:",to) //即将进入的路由的信息
	    console.log("from:",from) //当前即将离开的路由信息

	    next()

	    /*
	        if(to.name == "history"){
	            next(false) //拦截
	        }else{
	            next() //继续
	        }
	    */
	})

	app.mount('#app')