下拉式Tab

.has_children{background:#555;color:#FF0000;cursor:pointer;}div{padding:0;margin:0px 0;}div a{background:#888;display:none;float:left;width:300px;}.highlight{color:#FF00FF;background:#cccccc;}$(".has_children").click(function(){$(this).addClass("highlight").children("a").show().end().siblings().removeClass("highlight").children("a").hide();})<div id="menu"><div id="content" class="has_children"> <span>第一章</span> <a>链接11</a> <a>链接12</a> <a>链接13</a> <a>链接14</a> <a>链接15</a></div><div id="content" class="has_children"> <span>第2章</span> <a>链接21</a> <a>链接22</a> <a>链接23</a> <a>链接24</a> <a>链接25</a></div><div id="content" class="has_children"> <span>第3章</span> <a>链接31</a> <a>链接32</a> <a>链接33</a> <a>链接34</a> <a>链接35</a></div></div>