<!DOCTYPE html>
<html>
<head>
<meat charset="UTF-8">
<title>2_react生命周期（旧）</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 Count extends React.Component{
//构造器
constructor(props){
console.log('Count---constructor');
super(props)
//初始化状态
this.state = { count: 0 }
}
//加1按钮的回调
add = ()=>{
//获取原状态
const {count} =this.state
//更新状态
this.setState({count: count+1})
}
//组件将要挂载的钩子
componentWillMount(){
console.log('Count---componentWillMount');
}
//组件挂载完毕的钩子
componentDidMount(){
console.log('Count---componentDidMount')
}
render(){
console.log('Count---render')
const {count}=this.state
return(
<div>
<h2>当前求和为：{count}</h2>
<button onClick={this.add}>点我+1</button>
</div>
)
}
}
//2.渲染组件到页面
ReactDOM.render(<Count/>, document.getElementById("test"));
</script>
</body>
</html>
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