JS模拟的QQ面板上的多级可展开的菜单

<meta http-equiv="Content-Type" content="text/html;charset=UTF-8"> <title>qq菜单</title> <style> body { font-family: verdana, helvetica, arial, sans-serif; } #mainmenu { background-color: #eee; border: 1px solid #ccc; color: #000; width: 203px; } #menulist { margin: 0px; padding: 10px 0px 10px 15px; } li.menubar { background: url() no-repeat 0em 0.3em; font-size: 12px; line-height: 1.5em; list-style: none outside; } .menu, .submenu { display: none; margin-left: 15px; padding: 0px; } .menu li, .submenu li { background: url() no-repeat 0em 0.3em; list-style: none outside; } a.actuator { background-color: transparent; color: #000; font-size: 12px; padding-left: 15px; text-decoration: none; } a.actuator:hover { text-decoration: underline; } .menu li a, .submenu li a { background-color: transparent; color: #000; font-size: 12px; padding-left: 15px; text-decoration: none; } .menu li a:hover, submenu li a:hover { text-decoration: underline; } span.key { text-decoration: underline; } </style> <div id="mainmenu"> <ul id="menulist"> <li class="menubar"> <a href="#" id="productsactuator" class="actuator">我有朋友圈</a> <ul id="productsmenu" class="menu"> <li> <a href="#" id="newphonesactuator" class="actuator">我的好友</a> <ul id="newphonesmenu" class="submenu"> <li> <li> <li> </ul> </li> <li> <a href="#" id="compareactuator" class="actuator">陌生人</a> <ul id="comparemenu" class="submenu"> <li> <li> </ul> </li> </ul> </li> </ul> </div>
[ctrl+a 全选 注:如需引入外部js需刷新才能执行]