index-01b

HTML

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>React</title>
</head>
<body>
<div id="root"></div>
<script src='//unpkg.com/react/umd/react.development.js'></script>
<script src='//unpkg.com/react-dom/umd/react-dom.development.js'></script>
<script >
    ReactDOM.render(
    React.createElement('h1', null, 'Hello, world!'),
    document.getElementById('root'));
</script>
</body>
</html>