// --- 获取ClassName
    document.getElementsByClassName = function(cl) {
        var retnode = [];
        var myclass = new RegExp('\\b'+cl+'\\b');
        var elem = this.getElementsByTagName('*');
        for (var j = 0; j < elem.length; j++) {
            var classes = elem[j].className;
            if (myclass.test(classes)) retnode.push(elem[j]);
        }
        return retnode;
    }
    
    // --- 隐藏所有
    function HideAll() {
        var items = document.getElementsByClassName("optiton");
        for (var j=0; j<items.length; j++) {
            items[j].style.display = "none";
        }
    }
    
    // --- 设置cookie
    function setCookie(sName,sValue,expireHours) {
        var cookieString = sName + "=" + escape(sValue);
        //;判断是否设置过期时间
        if (expireHours>0) {
             var date = new Date();
             date.setTime(date.getTime + expireHours * 3600 * 1000);
             cookieString = cookieString + "; expire=" + date.toGMTString();
        }
        document.cookie = cookieString;
    }
    
    //--- 获取cookie
    function getCookie(sName) {
      var aCookie = document.cookie.split("; ");
      for (var j=0; j < aCookie.length; j++){
        var aCrumb = aCookie[j].split("=");
        if (escape(sName) == aCrumb[0])
          return unescape(aCrumb[1]);
      }
      return null;
    }
    
    window.onload = function() {
        var show_item = "opt_1";
        if (getCookie("show_item") != null) {
             show_item= "opt_" + getCookie("show_item");
        }
        document.getElementById(show_item).style.display = "block";
        var items = document.getElementsByClassName("subnavtit");
        for (var j=0; j<items.length; j++) {
            items[j].onclick = function() {
                var o = document.getElementById("opt_" + this.name);
                if (o.style.display != "block") {
                    HideAll();
                    o.style.display = "block";
                    setCookie("show_item",this.name);
                }
                else {
                    o.style.display = "none";
                }
            }
        }
    }