function addCookie(objName,objValue,objHours)
{//添加cookie
   var str = objName + "=" + escape(objValue);
   if(objHours > 0){//为0时不设定过期时间,,浏览器关闭时cookie自动消失
    var date = new Date();
    var ms = objHours*3600*1000;
    date.setTime(date.getTime() + ms);
    str += "; expires=" + date.toGMTString();
   }
   document.cookie = str;
   alert("添加cookie成功");
  }
  
  //获取指定名称(的)cookie(的)值

  function getCookie(sName){
        var aCookie = document.cookie.split("; ");
        for (var i=0; i < aCookie.length; i++){
            var aCrumb = aCookie[i].split("=");
            if (sName == aCrumb[0]){
               return unescape(aCrumb[1]);
            }
        }
    }
  
  function delCookie(name)
  {//为了删除指定名称(的)cookie,,可以将其过期时间设定为一个过去(的)时间
   var date = new Date();
   date.setTime(date.getTime() - 10000);
   document.cookie = name + "=a; expires=" + date.toGMTString();
  }
  
  function allCookie()
  {//读取所有保存(的)cookie字符串

   var str = document.cookie;
   if(str == "")
   {
    str = "没有保存任何cookie";
   }
   alert(str);
  }