[Artic]

//class A Root
private function createNewClassB():void
{
    var sameClassB:ClassB = new ClassB();
    sameClassB.addEventListener(ClassB.HELLOWORLD, testMessagefromClassB);
    addChild(sameClassB);

}
private function testMessagefromClassB(event:Event):void
{
    // im here
}

//class B
public static var HELLOWORLD:String = "helloworld";
public function ClassB()
{
var sameSprite:Sprite = new Sprite();
sameSprite.graphics.beginFill(0x666666);
sameSprite.graphics.drawRect( 0, 0, 50,50);
sameSprite.graphics.endFill();
sameSprite.addEventListener(MouseEvent.CLICK, sendMessage);
addChild(sameSprite);
}
private function sendMessage(event:Event):void
{
    dispatchEvent(new Event(ClassB.HELLOWORLD,true));
}