use XML::LibXML::Reader;
my $reader = XML::LibXML::Reader->new(string => $html, recover => 2);
while ($reader->read) {
    processNode($reader);
}

sub processNode {
    my $reader = shift;
    printf "%d %d %s %s\n", ($reader->depth,
                             $reader->nodeType,
                             $reader->name,
                             $reader->value);
}