<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <script src="./node_modules/react/umd/react.development.js"></script>
    <script src="./node_modules/react-dom/umd/react-dom.development.js"></script>
    <script src="./node_modules/babel-standalone/babel.min.js"></script>
    <script src="./node_modules/prop-types/prop-types.js"></script>
</head>
<body>
<div id="demoReact">

</div>
<script type="text/babel">
    class Com extends  React.Component{
        constructor(props) {
            super(props);
            this.state={
                name:"画画",

            }
        }
    fun=()=>{
           console.log(this.refs.demoInput.value)
    }
        render(){
            return(
                <div>
                    <input type="text" ref="demoInput" placeholder="请输入"/>
                    <button onClick={this.fun}>点我</button>

                </div>
        )
        }
        }

        ReactDOM.render(<Com/>,document.getElementById('demoReact'))



</script>
</body>
</html>

运行结果