AngularJS—06数据处理

<h2>我的笔记</h2>
	<p><textarea ng-model="txt" cols="40" rows="10"></textarea></p>
	
	<p>
		<button ng-click="save()">保存</button>
		<button ng-click="clear()">清除</button>
	
	</p>
		<p>Number of characters left:{{num()}}</p>