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

function getcookie(name)
{
  l = document.cookie.indexOf(name + "=");
  if (l == -1) return null;
  l += name.length + 1;

  r = document.cookie.indexOf(";", l);
  if (r == -1) r = document.cookie.length;

  return document.cookie.substring(l, r);
}

function clearcookie(name)
{
  now = new Date();
  setcookie(name, "", now);
}