function getCookie(name)
 {
  var dc=document.cookie;
  var prefix=name+"=";
  var begin=dc.indexOf("; "+prefix);
  if(begin==-1)
  {
   begin=dc.indexOf(prefix);
   if(begin!=0){
    return "";
   }
  }
  else
   begin+=2;
  var end=document.cookie.indexOf(";",begin);
  if(end==-1)
   end=dc.length;
  return unescape(dc.substring(begin+prefix.length,end));
 }

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

 //
 function setCookie(name,value)
 {
  var expires=new Date();
  
  expires.setTime(expires.getTime()+30*24*60*60*1000); 
  document.cookie=name+"="+escape(value)+"; expires="+expires.toGMTString()+"; path=/";
 }