prepare to detach ui to cnd, so write
index.html
<script src="https://unpkg.com/element-ui@2.2.2/lib/index.js"></script>
<link rel="stylesheet" href="https://unpkg.com/element-ui@2.2.2/lib/theme-chalk/index.css">
after adding and commenting out the element
npm start in main.js, the home page prompt cannot find the component? What"s the problem?