import React,{Component} from ‘react‘ import ReactDOM from ‘react-dom‘ class App extends Component{ //给一个初始化状态 constructor(){ super(); this.state={ result:0 } } handChange=()=>{ //获取input a的类容,这个a就是我们给的标识ref="a" let a=this.refs.a.value||0; let b=this.refs.b.value||0; //改变状态,更新视图 this.setState({result:parseFloat(a)+parseFloat(b)}) } render(){ return ( <div> <input type="text" ref="a" onChange={this.handChange}/> + <input type="text" ref="b" onChange={this.handChange}/> <p>{this.state.result}</p> </div> ) } } ReactDOM.render(<App/>,document.querySelector("#root"))
时间: 2024-10-06 09:21:12