Try this:

#!/usr/bin/perl -w
 
use strict;
use LWP::UserAgent;
use URI::URL;
 
my $ua = new LWP::UserAgent;
 
my $page = "http://lsa.colorado.edu/cgi-bin/LSA-sentence-x.html";
 
my $uri = new URI::URL;
$uri->query_form("LSAspace" => "General_Reading_up_to_1st_year_college
+ (300 factors)",
                 "LSAFactors" => "",
                 "txt1" => "I hate Jimmy. I love Jimmy.");
 
my $req = new HTTP::Request POST => $page;
$req->content_type('application/x-www-form-urlencoded');
$req->content($uri->equery);
 
my $res = $ua->request($req);
 
if (!$res->is_success) {
  die "Fetch failed\n";
}
 
my $content = $res->content;
print $content;
[download]