HTML

我们在#menu多个li一级菜单，在它的next节点放置二级菜单ul和三级菜单ul li ul

<ul id="menu"> <li class="l1"><a href="javascript:c(m01);" id="m01"><span><img src="images/ico/2.gif" align="absMiddle"/> 我的办公桌</span></a></li> <ul id="m01d" style="display:none;" class="U1"> <li class="l21"><a href="javascript:c(f41);" id="f41"><span><img src="images/ico/2.gif" align="absMiddle"/> 短信息</span></a></li> <ul id="f41d" style="display:none;"> <li class="l3"><a href="javascript:a('sms','3');" id="f3"><span><img src="images/ico/2.gif" align="absMiddle"/>内部短信</span></a></li> <li class="l3"><a href="javascript:a('mobile_sms','42');" id="f42"><span><img src="images/ico/2.gif" align="absMiddle"/>手机短信</span></a></li> </ul> <li class="l22"><a href="javascript:a('notify/show','4');" id="f4"><span><img src="images/ico/2.gif" align="absMiddle"/> 公告通知</span></a></li> </ul> </ul>

jQuery

菜单点击事件

function c(srcelement) {
    var targetid, srcelement, targetelement;
    var strbuf;

    //-------- 如果点击了展开或收缩按钮---------
    targetid = srcelement.id + "d";
    targetelement = document.getElementById(targetid);

    if (targetelement.style.display == "none") {
        srcelement.className = "active";
        targetelement.style.display = '';

        menu_flag = 0;
        expand_text.innerHTML = "收缩";
    } else {
        srcelement.className = "";
        targetelement.style.display = "none";

        menu_flag = 1;
        expand_text.innerHTML = "展开";
        var links = document.getElementsByTagName("A");
        for (i = 0; i < links.length; i++) {
            srcelement = links[i];
            if (srcelement.parentNode.className.toUpperCase() == "l1" && srcelement.className == "active" && srcelement.id.substr(0, 1) == "m") {
                menu_flag = 0;
                expand_text.innerHTML = "收缩";
                break;
            }
        }
    }
}

设置当前菜单选中样式

function set_current(id) {
    cur_link = document.getElementById("f" + cur_id) if (cur_link) cur_link.className = "";
    cur_link = document.getElementById("f" + id);
    if (cur_link) cur_link.className = "active";
    cur_id = id;
}