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">
        /**
         * ref绑定
         * 1.在定义部分 声明ref的名字  来自于React.createRef()
         * 2.在jsx部分 使用 ref={xxxx}
         * 3.输出 {current:绑定的ref元素}
        */
        let root = ReactDOM.createRoot(document.getElementById("root"));
        let countRef = React.createRef();
        let inpRef = React.createRef();
        function App() {
            function handleClick() {
                console.log(countRef)
                console.log(inpRef)
            }
            return (
                <div>
                    <Count ref={countRef} />
                    <button onClick={handleClick}>哈哈哈</button>
                    <input type="text" ref={inpRef} />
                </div>
            )
        }
        class Count extends React.Component {
            constructor(props) {
                super(props);
                this.state = {
                    aa: 20
                }
            }
            render() {
                return (
                    <div>
                        {this.state.aa}
                    </div>
                )
            }
        }
        root.render(<App/>);
    </script>
</body>

</html>