OA系统左侧分类导航伸缩菜单是一款非常漂亮实用的适用于OA系统、CRM系统、CMS系统等后台管理系统左侧分类功能导航的伸缩菜单。-OA classification system on the left navigation menu stretching is a very beautiful and practical apply to OA system, CRM systems, CMS systems and other back office systems classificati