function setCookie(name, value, expires) {
   document.cookie = escape(name) + "=" + escape(value) + "; path=/" + ((expires == null) ? "" : "; expires=" + expires.toGMTString());
}


function getCookie(name) {
   var cookiename = name + "=";
   var dc = document.cookie;
   var begin, end;

   if (dc.length > 0) {
       begin = dc.indexOf(cookiename);
       if (begin != -1) {
           begin += cookiename.length;
           end = dc.indexOf(";", begin);
           if (end == -1) {
               end = dc.length;
           }
           return unescape(dc.substring(begin,end));
       }
    }
    return null;
}

function deleteCookie(name) {
   document.cookie = name + "=; expires=Thu, 01-Jan-70 00:00:01 GMT" + "; path=/";
}