Event.target confusion?

Question

I'm trying to reusing function by using event.target, but after searching and trying different method online, I found the hardest part to understand is event.target part...
can anyone please explain to me what is the difference between(the example on right showing where I encounter those code):
1.event.target
2.event.target.name
3.event.currentTarget                             //e.g. event.currentTarget.addChild(myMc);
4.event.currentTarget.name                    //e.g. var newswf:URLRequest= new URLRequest( event.target.name +".swf");
5. MovieClip(event.currentTarget)            //e.g. addChild(MovieClip(event.currentTarget));

Answer 1

I believe that Circle is extending MovieClip so it is MovieClip. The circle is many things, you just have to say the compiler which one you mean
This is the inheritance of MovieClip:
MovieClip  Sprite DisplayObjectContainer InteractiveObject DisplayObject EventDispatcher Object
The main culprit is the event.currentTarget property, which returns the safest option, Object. But it doesn't mean the circle becames only Object and nothing more, it means that the circle is just treated as just-an-object until you explicitly say "treat it as a MovieClip" by casting it as MovieClip: MovieClip(event.currentTarget).