<!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>