实现效果：
HTML代码：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>手风琴效果</title>
</head>
<body>
<div class="main">
<ul id="expand">
<li>
<h3 class="h3-common">第一类目</h3>
<ul>
<li>1</li>
<li>2</li>
<li>3</li>
<li>4</li>
</ul>
</li>
<li>
<h3 class="h3-common">第二类目</h3>
<ul>
<li>5</li>
<li>6</li>
<li>7</li>
</ul>
</li>
<li>
<h3 class="h3-common">第三类目</h3>
<ul>
<li>8</li>
<li>9</li>
<li>10</li>
<li>11</li>
</ul>
</li>
<li>
<h3 class="h3-common">第四类目</h3>
<ul>
<li>12</li>
<li>13</li>
<li>14</li>
<li>15</li>
</ul>
</li>
</ul>
</div>
</body>
</html>
CSS代码：
/*
* by @Kevinの快乐时代
*2015/5/21
*/
*{
margin: 0;padding: 0;
}
ul,li{
list-style: none;
}
.main{
300px;
color:#666;
position: absolute;
top: 0;
right: 0;
bottom: 0;
left: 0;
margin:auto;
}
.main ul li ul{
display: none;
padding: 15px;
background-color: #ecf0f1;
}
#expand li ul li {
padding: 5px 0;
border-bottom: 1px dotted #999;
}
.h3-common{
font-size: 15px;
color: #fff;
padding: 5px 22px;
border-bottom: 1px dotted #e7e7e7;
}
.main h3{
background: url(http://www.iconfont.cn/uploads/fonts/font-155705-.png?color=ecf0f1&size=20) no-repeat #00bb9c left center;
}
.main h3.active{
background: url(http://www.iconfont.cn/uploads/fonts/font-69084-.png?color=ecf0f1&size=20) no-repeat #ea8010 left center;
}
.li_active{
background-color: #56abe4;
color: #fff;
text-align: center;
border-radius: 3px;
}
javascript代码：
var oExpand=document.getElementById('expand');
var ah3=oExpand.getElementsByTagName('h3');
var aUl=oExpand.getElementsByTagName('ul');
var aLi=null;
var arrLi=[];
for(var i=0;i<ah3.length;i++){
ah3[i].index=i;
ah3[i].onclick=function(){
var current_num=this.index;//添加自定义索引值
for(var i=0;i<aUl.length;i++){
//没被选中的ul折叠起来
if(ah3[i] != this){
ah3[i].className="h3-common";
aUl[i].style.display="none";
}
}
//展开，收起
if(!ah3[current_num].classList.contains('active')){
ah3[current_num].classList.add('active');
aUl[current_num].style.display='block';
}else{
ah3[current_num].classList.remove('active');
aUl[current_num].style.display='none';
}
}
}
//添加数组
for(var i=0;i<aUl.length;i++){
aLi =aUl[i].getElementsByTagName('li');
for(var j=0;j<aLi.length;j++){
arrLi.push(aLi[j]);
}
}
for(var i=0;i<arrLi.length;i++){
arrLi[i].onclick=function(){
//初始化其他li
for(var i=0;i<arrLi.length;i++){
if(arrLi[i] !=this){
arrLi[i].className='';
}
}
//元素本身的点击选中，再点击消失；.li_active是选中时的状态
if(!this.classList.contains('li_active')){
this.classList.add('li_active');
}else{
this.classList.remove('li_active')
}
}
}