网页左侧黑色竖直三级导航菜单基于jquery-1.4.2.min.js制作，单击一级菜单竖直显示二级菜单，三级菜单目录可显示图片。-The left side of the page three black vertical navigation menu based on jquery-1.4.2.min.js production, click a menu displayed vertically secondary menu, three menu tree to display the