function EcrireCookie (nom,valeur,expires,path,domain,secure) {
      document.cookie = nom + "=" + escape (valeur) +
        ((expires) ? "; expires=" + expires.toGMTString() : "") +
        ((path) ? "; path=" + path : "") +
        ((domain) ? "; domain=" + domain : "") +
        ((secure) ? "; secure" : "");
    }
function getCookieVal(offset)
{
   var endstr=document.cookie.indexOf (";", offset);
   if (endstr==-1) endstr=document.cookie.length;
   return unescape(document.cookie.substring(offset, endstr));
}
function LireCookie(nom)
{
   var arg=nom+"=";
   var alen=arg.length;
   var clen=document.cookie.length;
   var i=0;
   while (i<clen)
   {
      var j=i+alen;
      if (document.cookie.substring(i, j)==arg) return getCookieVal(j);
      i=document.cookie.indexOf(" ",i)+1;
      if (i==0) break;
   }
   return null;
}

Cybtr=LireCookie("Cybtr");
Cybtr++;
date=new Date;
date.setMonth(date.getMonth()+6);
EcrireCookie("Cybtr", Cybtr,date);