Install react (abbreviated) The introduction of react external links

Install scaffolding

1. npm i -g create-react-app or yarn global add create-react-app
2. create-react-app userThe name created by the user who created the project can be modified by itself and cannot contain Chinese and uppercase letters
3. cd user
4. yarn start

React external connection introduction

Introduction react core library
<script src="https://cdn.bootcdn.net/ajax/libs/react/16.13.1/umd/react.development.js"></script>
introduced react-dome supported react operations dom
<script src="https://cdn.bootcdn.net/ajax/libs/react-dom/16.13.1/umd/react-dom.development.js"></script>
introduced babel will jsx converted to js
<script src="https://unpkg.com/@babel/standalone/babel.min.js"></script>