use strict;
use warnings;
use WWW::Mechanize;

my $agent = WWW::Mechanize->new();
$agent->get('http://localhost/cgi-bin/foo.cgi');
$agent->form(1);
$agent->field(qw(text1 HELO));
$agent->field(qw(checkbox1 foo 1));
$agent->field(qw(checkbox1 baz 3));
$agent->click('go');

print ($agent->{content} =~ /<pre>(.*)<\/pre>/s);