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                <!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 Button extends React.Component {
  constructor(props) {
    super(props);
    this.state = { data: 0 };
    this.setNewNumber = this.setNewNumber.bind(this);
  }

  setNewNumber() {
    this.setState({ data: this.state.data + 1 });
  }

  render() {
    return (
      <div>
        <button onClick={this.setNewNumber}>INCREMENT</button>
        <Content myNumber={this.state.data} />
      </div>
    );
  }
}

class Content extends React.Component {
  componentDidMount() {
    console.log("Component DID MOUNT!");
  }

  shouldComponentUpdate(newProps, newState) {
    return true;
  }

  componentDidUpdate(prevProps, prevState) {
    console.log("Component DID UPDATE!");
  }

  componentWillUnmount() {
    console.log("Component WILL UNMOUNT!");
  }

  render() {
    return (
      <div>
        <h3>{this.props.myNumber}</h3>
      </div>
    );
  }
}

const root = ReactDOM.createRoot(document.getElementById("root"));
root.render(
  <div>
    <Button />
  </div>
);
</script>


</body>
</html>
              