带有弹出式菜单的按钮可以使一个按钮具有多项选择功能，扩展了按钮的功能，相当于把多个按钮集成于一体，可以减少按钮数目。-with pop-up menu button can make a button with a number of options, extending the functions of the button, to make the buttons more integrated one, we can reduce the number of buttons.

Javascr ipt编写的目录树菜单 目录树代码 V1.21 .无限分类 .以\"-\"数目表示层数,清晰明了 .动态展开&收缩 天窗 http://www.faisun.com 暖阳 faisun@sina.com 2004 年 11 月-Javascr ipt prepared by the tree menu tree code V1.21. Unlimited classification. "-" Number, said the number of layers