我只有在这个class中没有none的时候才会出现二级菜单，有none就会出来一个细一点的框，<div id="sub" class=""> <div id="a" class="sub_content" >
<body>
<div class="wrap" id="test">
<ul>
<li data-id="a">
<span>家用电器</span>
</li>
<li data-id = "b">
<span>手机 /运营商 /数码</span>
</li>
<li data-id ="c">
<span>电脑办公</span>
</li>
<li data-id ="d">
<span>家具 /家居 /家装 /厨具</span>
</li>
<li data-id ="e">
<span>男装 /女装 /童装 /内衣</span>
</li>
<li data-id = "f">
<span>化妆品 /清洁用品 /宠物</span>
</li>
<li data-id = "g">
<span>鞋靴 /箱包 /珠宝 /奢侈品</span>
</li>
<li data-id = "h">
<span>运动 /户外 /钟表</span>
</li>
<li data-id = "i">
<span>汽车 /汽车用品</span>
</li>
<li data-id = "j">
<span>女婴 /玩具乐器</span>
</li>
<li data-id = "k">
<span>食品 /酒类 /生鲜 /特产</span>
</li>
<li data-id = "l">
<span>医药保健</span>
</li>
</ul>
<div id="sub" class="">
<div id="a" class="sub_content" >
<dl>
<dt>
<a href="#" target="_blank">电视<i>></i></a>
</dt>
<dd class="first">
<a href="#" target="_blank">合资品牌</a>
<a href="#" target="_blank">国产品牌</a>
<a href="#" target="_blank">互联网品牌</a>
</dd>
</dl>
<dl>
<dt>
<a href="#" target="_blank">空调<i>></i></a>
</dt>
<dd>
<a href="#" target="_blank">壁挂式空调</a>
<a href="#" target="_blank">柜式空调</a>
<a href="#" target="_blank">中央空调</a>
<a href="#" target="_blank">空调配件</a>
</dd>
</dl>
<dl>
<dt>
<a href="#" target="_blank">洗衣机<i>></i></a>
</dt>
<dd>
<a href="#" target="_blank">滚筒洗衣机</a>
<a href="#" target="_blank">洗烘一体机</a>
<a href="#" target="_blank">波轮洗衣机</a>
<a href="#" target="_blank">迷你洗衣机</a>
<a href="#" target="_blank">洗衣机配件</a>
</dd>
</dl>
<dl>
<dt>
<a href="#" target="_blank">冰箱<i>></i></a>
</dt>
<dd>
<a href="#" target="_blank">多门</a>
<a href="#" target="_blank">对开门</a>
<a href="#" target="_blank">三门</a>
<a href="#" target="_blank">双门</a>
<a href="#" target="_blank">冷柜/冰吧</a>
<a href="#" target="_blank">酒柜</a>
<a href="#" target="_blank">冰箱配件</a>
</dd>
</dl>
</div>
</div>
</div>
