1hello.html

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>hello react</title>
</head>
<body>
  <div id="app">
    <!-- view 랜더링 -->
  </div>
  <script src="react/build/react.js"></script>
  <script src="react/build/react-dom.js"></script>
  <script>
    //app code
      ReactDOM.render(
        //React.DOM.h1({id : "my-heading"}, "Hello world!"),
        React.DOM.h1({id : "my-heading", className: "main-head", style: {color: "#eeeeee", background: "#777777"}},
          React.DOM.span(null,
            React.DOM.em(null, "HELL"),
            "o "
            ),
          "world"
        ),
        document.getElementById("app")
      );
  </script>
  <scrip>

</body>
</html>