JS 文件
<script type="text/javascript">

$(document).ready(function(){

    $(".level1 > a").click(function(){

        $(this).addClass("current")   //给当前元素添加"current"样式

        .next().show()                //下一个元素显示

        .parent().siblings().children("a").removeClass("current")        //父元素的兄弟元素的子元素<a>移除"current"样式

        .next().hide();                //它们的下一个元素隐藏

        return false;

    });

});

</script>

HTML文件
<div class="box">

    <ul class="menu">

       <li class="level1">

            <a href="#none">衬衫</a>

            <ul class="level2">

                <li><a href="#none">短袖衬衫</a></li>

                <li><a href="#none">长袖衬衫</a></li>

                <li><a href="#none">短袖T恤</a></li>

                <li><a href="#none">长袖T恤</a></li>

            </ul>

        </li>

        <li class="level1">

            <a href="#none">卫衣</a>

            <ul class="level2">

                <li><a href="#none">开襟卫衣</a></li>

                <li><a href="#none">套头卫衣</a></li>

                <li><a href="#none">运动卫衣</a></li>

                <li><a href="#none">童装卫衣</a></li>

            </ul>

        </li>

        <li class="level1">

            <a href="#none">裤子</a>

            <ul class="level2">

                <li><a href="#none">短裤</a></li>

                <li><a href="#none">休闲裤</a></li>

                <li><a href="#none">牛仔裤</a></li>

                <li><a href="#none">免烫卡其裤</a></li>

            </ul>

        </li>

    </ul>

</div>

/* reset */

body{margin:;padding:  12px ;font-size:12px;line-height:22px;font-family:"\5b8b\4f53","Arial Narrow";background:#fff;}

form,ul,li,p,h1,h2,h3,h4,h5,h6{margin:;padding:;}

input,select{font-size:12px;line-height:16px;}

img{border:;}

ul,li{list-style-type:none;}

a {color:#00007F;text-decoration:none;}

a:hover {color:#bd0a01;text-decoration:underline;}

.box {

    width: 150px;

    margin:  auto;

}

.menu{

    overflow:hidden;

    border-color: #C4D5DF;

    border-style: solid;

    border-width:  1px 1px;

}

/* lv1 */

.menu li.level1 a{

    display: block;

    height: 28px;

    line-height: 28px;

    background:#EBF3F8;

    font-weight:;

    color: #5893B7;

    text-indent: 14px;

    border-top: 1px solid #C4D5DF;

}

.menu li.level1 a:hover{text-decoration:none;}

.menu li.level1 a.current{background:#B1D7EF;}

/* lv2 */

.menu li ul{overflow:hidden;}

.menu li ul.level2{display:none;}

.menu li ul.level2 li a{

    display: block;

    height: 28px;

    line-height: 28px;

    background:#ffffff;

    font-weight:;

    color: #42556B;

    text-indent: 18px;

    border-top: 0px solid #ffffff;

    overflow: hidden;

}

.menu li ul.level2 li a:hover{

    color:#f60;
}