https://rein.kr/posts/2008-05-06-actionscript-%EA%B0%9C%EB%B0%9C%ED%99%98%EA%B2%BD%EC%9D%84-%EC%A0%95%EB%A7%90-%EC%9D%B4%EB%A0%87%EA%B2%8C-%EB%B0%96%EC%97%90-%EB%AA%BB-%EB%A7%8C%EB%93%9C%EB%82%98/