#!/usr/bin/perl -w

use strict;
use HTML::Parser;

my $parser = HTML::Parser->new(
    start_h => [ \&_starttag, 'self, tagname, attr' ],
    end_h   => [ \&_endtag,   'self, tagname' ],
    text_h  => [ \&_text,     'self, dtext' ]
);

my @chunks;
$parser->parse_file(\*DATA);

print "----------\n$_\n----------\n\n" for @chunks;

sub _starttag {
    my ($self, $tag, $attr) = @_;
    $self->{'_pre'} = 1 if ($tag eq 'pre');
}

sub _endtag {
    my ($self, $tag) = @_;
    $self->{'_pre'} = undef if ($tag eq 'pre');
}

sub _text {
    my ($self, $dtext) = @_;

    $dtext =~ s/\A\s+//;
    $dtext =~ s/\s+\z//;
    return() unless ( length($dtext) > 0 and $dtext =~ /[^\s]/ );

    if ( defined($self->{'_pre'}) ) {
        push(@chunks, "PRE: $dtext");
    }
    else {
        push(@chunks, "TEXT: $dtext");
    }
}

__END__
<p>This is a bad try to display text then code
<pre>#! usr/bin/perl
use strict;
use warnings;

print "Hello World!";</pre>
and then plain text again</p>