添加多个tab，并循环修改tab样式

 <div class="con">
        <ul >
                第六周</a> </li>
        </ul>

        <script type="text/javascript">
            function selectTag(showContent, selfObj) {
                // 操作标签
                var tag = document.getElementById("tags").getElementsByTagName("li");
                var taglength = tag.length;
                for (i = 0; i < taglength; i++) {
                    tag[i].className = "";
                }
                selfObj.parentNode.className = "selectTag";
            }
        </script>

        <div ></iframe>
            </div>
        </div>
    </div>