sub check_bogus_html_tags {
  # now check for bogus tags:
  my ($body) = @_;
  my $reason = "";
  use HTML::Tagset;
  use HTML::PullParser;
  my $p = HTML::PullParser->new(
    doc   => \$body,
    start => '"S", tagname',
    end   => '"E", tagname',
  );
  my %seen;
  while (my $token = $p->get_token()) {
    my ($start,$tag) = @$token;
    $seen{$tag}++
      unless ($HTML::Tagset::isKnown{$tag} );
  };
  $reason = "Bogus tags " . join(" ",sort keys %seen) . "\n"
    if (scalar keys %seen > 10 );
};