  // --- 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("title");
          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";
                  }
              }
          }
      }