actionscript中this和super的指向问题

 1 package
 2 {
 3     import flash.display.Sprite;
 4     
 5     public class A extends Sprite
 6     {
 7         public function A()
 8         {
 9             trace(this+":A");
10             trace(super+":A");
11         }
12     }
13 }

 1 package
 2 {
 3     public class B extends A
 4     {
 5         public function B()
 6         {
 7             trace(this+":B");
 8             trace(super+":B");
 9         }
10     }
11 }

B是文档类，编译输出：

[object B]:A
[object B]:A
[object B]:B
[object B]:B