JS模拟的QQ面板上的多级可展开的菜单

QQ菜单

if (!document.getElementById)
document.getElementById = function() { return null; }
function initializeMenu(menuId, actuatorId) {
var menu = document.getElementById(menuId);
var actuator = document.getElementById(actuatorId);
if (menu == null || actuator == null) return;
actuator.parentNode.style.backgroundImage = "url(/images/plus.gif)";
actuator.onclick = function() {
var display = menu.style.display;
this.parentNode.style.backgroundImage =
(display == "block") ? "url(/images/plus.gif)" : "url(/images/minus.gif)";
menu.style.display = (display == "block") ? "none" : "block";
return false;
}
}
window.onload = function() {
initializeMenu("productsMenu", "productsActuator");
initializeMenu("newPhonesMenu", "newPhonesActuator");
initializeMenu("compareMenu", "compareActuator");
}

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;
}

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[Ctrl+A 全选 注:如需引入外部Js需刷新才能执行]