sub header_NS {
  # Assume that nobody uses Netscape anymore
  my $result = undef;

  # Get user agent passed as the only parameter
  my $user_agent = shift;

  if ($user_agent =~ m#^Mozilla/\d+#i) {
    # We have a Mozilla/NetScape compatible browser
    if ($user_agent !~ /compatible/i) {
      # And it's not even just "compatible", it's the real,
      # CSS burning, X crashing hellspawn
      $result = 1;
    };
  };

  return $result;
};