The Beginner's Guide to ReactJS by Kent C. Dodds

Hello_World_with_raw_React_APIs.html

<div id="root"></div>
<script src="unpkg.com/react@16.0.0/umd/react.production.min.js"></script>
<script src="unpkg.com/react-dom@16.0.0/umd/react-dom.production.min.js
"></script>

<script type="text/javascript"> 
//   const rootElement = document.getElementById('root');
//   const element = document.createElement('div');
//   element.textContent = 'Hello World';
//   element.className = 'container';
//   rootElement.appendChild(element);
  
  const rootElement = document.getElementById('root');
  const element = React.createElement(
    'div',
    {className: 'container'},
    'Hello World'
    )
  ReactDOM.render(element, rootElement)
</script>

using-jsx-02.html

<div id="root"></div>
<script src="unpkg.com/react@16.0.0/umd/react.production.min.js"></script>
<script src="unpkg.com/react-dom@16.0.0/umd/react-dom.production.min.js
"></script>
<script src="https://unpkg.com/babel-standalone@6/babel.min.js"></script>

<script type="text/babel"> 
  const rootElement = document.getElementById('root');
  
  const content = "hello world"
  const className = 'container'
  const props = { content, className }
  const element = <div{ ..props } />
  ReactDOM.render(element, rootElement)
</script>