use strict;
use warnings;

my $h_vars = {
    'name'           => '<h1>Fred Flintstone</h1>',
    'location'       => 'Bedrock',
    'favorite movie' => 'One <i>Million</i> Years B.C.',
    'favorite book'  => 'Danny the <b>Dinosaur</b>',
};

map { s/\</\&lt\;/g; s/\>/\&gt\;/g } values %$h_vars;

# Test code
use Data::Dumper;
printf "Results %s\n", Dumper($h_vars);

__END__

Results $VAR1 = {
          'location' => 'Bedrock',
          'favorite movie' => 'One &lt;i&gt;Million&lt;/i&gt; Years B.C.',
          'name' => '&lt;h1&gt;Fred Flintstone&lt;/h1&gt;',
          'favorite book' => 'Danny the &lt;b&gt;Dinosaur&lt;/b&gt;'
        };