一开始在浏览器运行Vue文件还可以的,之后写了HTML文件并运行后发现无论如何都无法回到原来的Vue文件了 {{ message }} let message = 'happpy birthday' setTimeout(() => { console.log('stringBeforeUpdate:'+ message) message = 'HAPPY BIRTHDAY' console.log('stringAfterUpdate:'+ message) }, 3000); import { createApp } from 'vue' import './style.css' import App from './components/message.vue' createApp(App).mount('#app') 11 尝试: 1、更改main.js文件的import App from './components/message.vue' 2、删除index.html 结果: 1、能运行回原来的message.vue