<!DOCTYPE html>
<html>
<head>
<meat charset="UTF-8">
<title>2_受控组件</title>
</head>
<body>
<!-- 准备好一个容器 -->
<div id="test"></div>
<!-- 核心库 -->
<script type="text/javascript" src="../js/react.development.js"></script>
<!-- react-dom,操作dom -->
<script type="text/javascript" src="../js/react-dom.development.js"></script>
<!-- 引入babel，jsx转为js -->
<script type="text/javascript" src="../js/babel.min.js"></script>
<!-- 此处一定要写babel -->
<script type="text/babel">
//1.创建组件
class Login extends React.Component{
//初始化状态
state ={
username:'',//用户名
password:''//密码
}
//保存用户名到状态中
saveUsername = (event)=>{
this.setState({username: event.target.value})
}
//保存密码到状态中
savePassword = (event) => {
this.setState({ password: event.target.value })
}
//表单提交的回调
handleSubmit = (event)=>{
event.preventDefault() //阻止表单提交
const {username,password} = this.state
alert(`你输入的用户名是：${username},你输入的密码是:${password}`)
}
render(){
return(
<form onSubmit={this.handleSubmit}>
用户名：<input onChange={this.saveUsername} type="text" name="username"/>
密码： <input onChange={this.savePassword} type="password" name="password"/>
<button>登录</button>
</form>
)
}
}
//2.渲染组件到页面
ReactDOM.render(<Login/>, document.getElementById("test"));
</script>
</body>
</html>
=================
受控的就是放入state了，alert是${username}，不用加.value,直接从state取；另外不用ref了；非受控每一个input都有一个ref
