<h1>---------------管道-------------</h1>
{{today | date:'yyyy-MM-dd HH:mm ss'}}

<h1>---------------事件(click)-----------------</h1>
<button (click)="run()">执行事件</button>
<button (click)="setData($event)">执行方法改变属性里面的数据</button>

<p>{{message}}</p>

<h1>------------表单事件(keydown)(keyup)----------------</h1>

keydown 刚按下
<input type="text" (keydown)="keyDown($event)" />

keyUp: 按下松开后
<input type="text" (keyup)="keyUp($event)" />