lovecoding
/
W250511


			
				
					
						
						
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							<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="./babel.min.js"></script>
    <script src="./react.development.js"></script>
    <script src="./react-dom.development.js"></script>
</head>

<body>
    <div id="root"></div>
    <script type="text/babel">
        // setState 更新组件状态state 触发组件重新渲染的核心方法
        let root = ReactDOM.createRoot(document.getElementById("root"));
        class Count extends React.Component {
            constructor(props) {
                super(props)
                this.state = {
                    count: 0
                }
            }
            handleClick = () => {
                // this.setState({
                //     count: 2
                // })
                this.setState((state,props) => ({
                    count: state.count + 1
                }))
            }
            render() {
                return (
                    <div>
                        <h1 onClick={this.handleClick}>{this.state.count}</h1>
                    </div>
                )
            }
        }
        // function Count() {
        //     return (
        //         <div><h1></h1></div>
        //     )
        // }
        root.render(<Count />);
    </script>
</body>

</html>