用is判断数据类型

package {import flash.display.Sprite;import flash.events.IEventDispatcher;import flash.events.EventDispatcher;public class SampleIs extends Sprite {public function SampleIs() {var a:Number=100;trace(a is Number);//输出：truetrace(a is String);//输出：falsetrace(a is Object);//输出：truevar foo:KingdaDispatcher=new KingdaDispatcher();trace(foo is KingdaDispatcher);//输出：truetrace(foo is EventDispatcher);//输出：truetrace(foo is IEventDispatcher);//输出：true}}}import flash.events.EventDispatcher;class KingdaDispatcher extends EventDispatcher {}

EventDispatcher类实现了IEventDispatcher接口，因此EventDispatcher可以看成是IEventDispatcher接口类型。