使用ref属性获取表单的数据
非受控组件:需要时才手动读取表单输入框中的数据
需求: 自定义包含表单的组件
- 输入用户名密码后, 点击登陆提示输入信息
- 不提交表单
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>09_form</title>
</head>
<body>
<div id="example"></div>
<script type="text/javascript" src="../js/react.development.js"></script>
<script type="text/javascript" src="../js/react-dom.development.js"></script>
<script type="text/javascript" src="../js/babel.min.js"></script>
<script type="text/babel">
class LoginFrom extends React.Component {
constructor (props) {
super(props)
this.handleSubmit = this.handleSubmit.bind(this)
}
render () {
return (
<form action="/test" onSubmit={this.handleSubmit}>
用户名:<input type="text" ref={input => this.userName = input}/>
密码:<input type="password" ref={input => this.userPass = input}/>
<input type="submit" value="登陆"/>
</form>
)
}
handleSubmit (event) {
const userName = this.userName.value
const userPass = this.userPass.value
alert(userName)
alert(userPass)
event.preventDefault() //阻止的默认行为(表单是的默认行为提交)
}
}
ReactDOM.render(<LoginFrom/>, document.getElementById('example'))
</script>
</body>
</html>
使用onChange事件
受控组件:表单项输入数据能自动收集成状态,
react的onChange事件跟原生的不一样,原生js的onChange是离开焦点之后才会触发,但是react中是输入一个字符触发一下
需求: 自定义包含表单的组件
- 输入用户名密码后, 点击登陆提示输入信息
- 不提交表单
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>09_form</title>
</head>
<body>
<div id="example"></div>
<script type="text/javascript" src="../js/react.development.js"></script>
<script type="text/javascript" src="../js/react-dom.development.js"></script>
<script type="text/javascript" src="../js/babel.min.js"></script>
<script type="text/babel">
class LoginFrom extends React.Component {
constructor (props) {
super(props)
// 初始化状态
this.state = {
pwd: ''
}
this.handleSubmit = this.handleSubmit.bind(this)
this.handleChange = this.handleChange.bind(this)
}
render () {
return (
<form action="/test" onSubmit={this.handleSubmit}>
用户名:<input type="text" ref={input => this.userName = input}/>
密码:<input type="password" value={this.state.pwd} onChange={this.handleChange}/>
<input type="submit" value="登陆"/>
</form>
)
}
handleChange (event) {
// 1.读取输入的值
const pwd = event.target.value
// 2.更新state下面对应的属性的状态
this.setState({pwd})
}
handleSubmit (event) {
const userName = this.userName.value
const {pwd} = this.state
alert(`用户名为${userName},密码为${pwd}`)
event.preventDefault() //阻止的默认行为(表单是的默认行为提交)
}
}
ReactDOM.render(<LoginFrom/>, document.getElementById('example'))
</script>
</body>
</html>