<div id="menu">
    <!--tag标题-->
    <div id="menu_female">
        <h3>女装</h3>
        <div class="tag" style="display: block;">
            <dl>
                <dd>
                    <p>第一类</p>
                    <a>1.衬衫</a>
                    <a>2.T恤</a>
                    <a>3.雪纺衫</a>
                    <a>4.针织衫</a>
                    <a>5.短外套</a>
                    <a>6.卫衣</a>
                    <a>7.小西裤</a>
                    <a>8.风衣</a>
                    <a>9.吊带背心</a>
                    <a>10.连衣裙</a>
                    <a name="setColor">11.蕾丝连衣裙</a>
                    <a>12.复古连衣裙</a>
                    <a>13.印花连衣裙</a>
                    <a>14.真丝连衣裙</a>
                    <a>更多</a>
                </dd>
            </dl>
        </div>

</div>

<script type="text/javascript">
    //不分男女，选中第一类衣服中第9个a元素，并改变颜色
    //这里用了nth-child 选择的他们所有父元素的第n个子元素
    $("#menu dd a:nth-child(9)").css('color','#66CD00');

</script>