cgi_starter/html/helloworld.cgi

#!/usr/bin/perl

use strict;
use warnings;

use CGI;

my $q = CGI->new;
print $q->header;

my $a = $q->param('a');
my $b = $q->param('b');

my $result;
$result = (scalar $a) + (scalar $b);

print <<EOF
<!DOCTYPE html>
<html>
  <head><title> Hello </title></head>
  <body>
    <h1> Hello World </h1>
    <p>
      $result
    </p>
  </body>
</html>
EOF