use WWW::Mechanize;
use Storable;
use LWP;
use warnings;
my $loginpage = "http://www.homepage.org";
my $challenge = "http://www.homepage.org/test.htm";

my $username = 'username'; 
my $password = 'password';

my $mech = WWW::Mechanize->new();
$mech -> cookie_jar(HTTP::Cookies->new());
$mech -> get($loginpage);
$mech -> form_name('loginform');
$mech -> field ('username' => $username);
$mech -> field ('password' => $password);
$mech -> click ('btn_submit');
#navigate to challenge page

$mech->get( $challenge );

my @find_text = $mech->find_all_inputs(
        type  => 'text'
    );

for $boxes (@find_text) {
#if (length($boxes->value) > 100) {
     print $boxes->value();
 # }
}
[download]

Here's a script that I did before you made your last post.

#!/usr/bin/perl 

use strict;
use warnings;
use Encode;
use URI::file;
use WWW::Mechanize;
use Data::Dumper::Concise;

my $page = 'http://www.perlmonks.org';
my $tmpfile = '/tmp/mech.log';

my $mech = WWW::Mechanize->new( cookie_jar => undef );
$mech->get( $page, ':content_file' => $tmpfile  );

my $uri = URI::file->new_abs( $tmpfile )->as_string;
my($field) = $mech->get( $uri );

open IN, '<', $tmpfile or die $!;
open OUT, '>', \*OUT or die $!;
binmode OUT, ":encoding(UTF-8)";

FIRST_FORM: {
    my $length = length(Encode::encode_utf8($field));
    my @find_text = $mech->find_all_inputs( type => 'text' );
    foreach my $find_text( @find_text ) {
        unless ($length > 100) {
            print Dumper( $find_text );
        }
    }
}
close IN;
close OUT;
[download]