AngularJS--$on、$emit和$broadcast的使用

<div ng-controller="EventController">
    Root scope
    <tt>MyEvent</tt> count: {{count}}
	<ul>
		<li ng-repeat="i in [1]" ng-controller="EventController">
			<button ng-click="$emit('MyEvent')">
				$emit('MyEvent')
			</button>
			<button ng-click="$broadcast('MyEvent')">
				$broadcast('MyEvent')
			</button>
			<br>
			Middle scope
			<tt>MyEvent</tt> count: {{count}}
			<ul>
				<li ng-repeat="item in [1, 2]" ng-controller="EventController">
					Leaf scope
					<tt>MyEvent</tt> count: {{count}}
				</li>
			</ul>
		</li>
	</ul>
</div>

function EventController($scope) {
	$scope.count = 0;
	$scope.$on('MyEvent', function() {
		$scope.count++;
	});
}