use LWP::Simple;
use XML::DTDParser;
my $dtdfile = "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd";
# or any other, like xhtml1-frameset.dtd
my $dtd = get($dtdfile);
$dtd =~ s/.*=== Imported Names =+-->//s; # avoid 'die' in XML::DTDParser
$DTD = ParseDTD $dtd;
my $elems = [ map {uc($_) } keys %$DTD ];
my %s;
my $attrs = [
    grep { s/-/_/g; ! $s{$_}++ }
    map { keys %{$DTD->{$_}->{'attributes'}} } keys %$DTD
];
define_vocabulary($elems,$attrs);