<li onClick="tab(this,'tab-list-8')">最新</li><li onClick="tab(this,'tab-list-8')">随机</li>

function tab(obj, id) {
    var shuzu_li = obj.parentNode.getElementsByTagName("li");
    var shuzu_nr = document.getElementById(id).getElementsByTagName("div");
    for (var i = 0; i < shuzu_nr.length; i++) {
        if (obj == shuzu_li[i]) {
            shuzu_li[i].className = "tab_current";
            shuzu_nr[i].className = "list-current"
        } else {
            shuzu_li[i].className = "";
            shuzu_nr[i].className = ""
        }
    }
}