React JS

1 install nodejs from https://nodejs.org/en/

2 install react by C:\Users\Your Name>npm install -g create-react-app

3 create react project C:\Users\Your Name>npx create-react-app myfirstreact

4 create an account in https://codesandbox.io/

5 torun project run C:\Users\Your Name\myfirstreact>npm start

6 open project in browser localhost:3000

001 React in HTML

<!DOCTYPE html>
<html>
  <script src="https://unpkg.com/react@16/umd/react.production.min.js"></script>
  <script src="https://unpkg.com/react-dom@16/umd/react-dom.production.min.js"></script>
  <script src="https://unpkg.com/babel-standalone@6.15.0/babel.min.js"></script>
  <body>
  
    <div id="mydiv"></div>

    <script type="text/babel">
      class Hello extends React.Component {
        render() {
          return <h1>Hello World!</h1>
        }
      }

      ReactDOM.render(<Hello />, document.getElementById('mydiv'))
    </script>
  </body>
</html>

002 React in Production