#!/usr/bin/perl
use WWW::Mechanize;
# URL for primer3
my $url = 'http://frodo.wi.mit.edu/cgi-bin/primer3/primer3_www.cgi';
my $mech = WWW::Mechanize->new();

$mech->get($url);
$sequence='ACAGCNTCTGTTGACTCCCCTGCCAGCAAGCCCACTGGCCTGAGCACATGAAGTCCTGCACCCAGTCAGGAGAAGGAGCGCTCCTGGCACCAGCAGGAGCTGGCAAAGGCTCTGGAGAGCTTAGAAAGGGAAAAAATGGAGCTGGAAATGAGGCTAAAGGAGCAGCAGACAGAAATGGAGGCCATCCAGGCCCAGAGGGAAGAAGAACGGACCCAGGCAGAGAGTGCCCTATGCCAGATGCAGCTGGAAACAGAGAAGGAGAGAGTATCCCTCCTGGAGACACTGCTGCAGACGCAGAAGGAGCTAGCAGATGCCAGCCAACAACTGGACGGAACTGAGGCAA';
$primernum='1';
$mech->submit_form(
        form_number => 1,
        fields      => {
            SEQUENCE    => $sequence,
            PRIMER_NUM_RETURN   => $primernum,
                       }
    );
# and so fourth...