// read for cookie
function getCookie(name){
  var cname = name + "=";               
  var dc = document.cookie;  
  if (dc.length > 0) {              
    begin = dc.indexOf(cname);       
    if (begin != -1) {           
      begin += cname.length;       
      end = dc.indexOf(";", begin);
      if (end == -1) end = dc.length;
        return unescape(dc.substring(begin, end));
    } 
  }
  return null;
}

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


// delete cookie.
function delCookie (name,path,domain) {
  if (getCookie(name)) {
    document.cookie = name + "=" +
    ((path == null) ? "" : "; path=" + path) +
    ((domain == null) ? "" : "; domain=" + domain);
//    "; expires=Thu, 01-Jan-70 00:00:01 GMT";
  }
}