public List<BBFlashMovie> getChildrenByClassName(string name){
if(name==null)
return null;
List<BBFlashMovie> children = new List<BBFlashMovie>();
for(int i=0; i<_depth_displays.Length; i++){
DisplayObject child = _depth_displays[i];
if(child!=null && child.className == name){
children.Add(child as BBFlashMovie);
}
}
return children.Count>0?children:null;
}