# if ($form_data{'box$i$j'} == "definitely not on")
 if ($form_data{"box$i$j"} eq "on")

##</code><code>##

#!/usr/bin/perl
use strict;
use warnings;
use CGI qw(:standard);
use CGI::Carp 'fatalsToBrowser';

my $query = new CGI;
print header,start_html();
check_test();
print end_html;

sub check_test(){
  print '<form name="form1" method="post" action="">';
  for my $i (1 .. 4){
    for my $j (1 .. 4){
      my $name  = "box$i$j";
      my $value = $query->param($name);
      if ($value eq "on"){
        print qq!<font color="#FF0000">Box $i$j:  $value</font><br/>!;
      } else {
        print qq!Box $i$j: <input type="checkbox" name="$name"> $value <br/>!;
      }
    }
  }
  print '<input type="submit" name="Submit" value="Submit"></form>';
}