菜鸟教程在线编辑器

AI 编程工具
 
                <!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8" />
<title>菜鸟教程 React 实例</title>
<script src="https://lf26-cdn-tos.bytecdntp.com/cdn/expire-1-M/react/18.2.0/umd/react.production.min.js" ></script>
<script src="https://lf3-cdn-tos.bytecdntp.com/cdn/expire-1-M/react-dom/18.2.0/umd/react-dom.production.min.js"></script>
<script src="https://lf9-cdn-tos.bytecdntp.com/cdn/expire-1-M/babel-standalone/6.26.0/babel.min.js" ></script>
</head>
<body>
<div id="root"></div>
<script type="text/babel">
class Header extends React.Component {
  constructor(props) {
    super(props);
    this.state = {favoritesite: "runoob"};
  }
  componentDidMount() {
    setTimeout(() => {
      this.setState({favoritesite: "google"})
    }, 1000)
  }
  componentDidUpdate() {
    document.getElementById("mydiv").innerHTML =
    "更新后喜欢的是 " + this.state.favoritesite;
  }
  render() {
    return (
      <div>
      <h1>我喜欢的网站是 {this.state.favoritesite}</h1>
      <div id="mydiv"></div>
      </div>
    );
  }
}
 
const root = ReactDOM.createRoot(document.getElementById("root"));
root.render(<Header />);
</script>

</body>
</html>
              