index.js
index.html
import React from 'react';
import ReactDOM from 'react-dom';
ReactDOM.render(<p>Hallo</p>, document.getElementById('sandy'));
//Click the "index.htm" tab to see the container "sandy".
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8" />
<meta name="viewport"
content="width=device-width, initial-scale=1" />
<title>React App</title>
</head>
<body>
<header id="sandy"></header>
</body>
</html>