03_Hello_React重构

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>

    <div id="root"></div>
    
    <script src="../lib/react.js"></script>
    <script src="../lib/react-dom.js"></script>
    <script src="../lib/babel.js"></script>

    <script type="text/babel">
        let message = "Hello World"

        function btnClick(){
            message = "Hello React"
            rootRender() 
        }

        const root = ReactDOM.createRoot(document.querySelector("#root"))


        function rootRender() {
            
            root.render((
                <div>
                    <h2>{message}</h2>
                    <button onClick={btnClick}>修改文本</button>    
                </div>

            ))
        }

        rootRender() 
    </script>
</body>
</html>