function getCookie(name)     {            var offset,cookieValue;         var search=name+"=";         if(document.cookie.length>0)         {             offset=document.cookie.indexOf(search);             if(offset!=-1)             {                 offset += search.length;                   end = document.cookie.indexOf(";", offset);                   if (end == -1)                     end = document.cookie.length;                   cookieValue=unescape(document.cookie.substring(offset, end));             }         }         return cookieValue;     } //name表示cookie的键的名字