use strict;
use CGI qw(:standard);

my @box = (qw(SSD PERS SS), 'CHILD SUP');

print header,
   start_html,
   start_form,
   checkbox_group(
      -name=>'type',
      -values=>\@box,
   ),
   p(submit('Go')),
   end_form,
;

if (param('Go')) {
   print p(hr), 'You picked:',
      ul(li[param('type')]),
   ;
}

print end_html;
[download]

jeffa

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)

I disagree. IT isn't really a solution to the problem either.
You might want to use the ? : construction. like

true ? print " selected" : print "";
[download]

I am sure that there are monks here who can explain this better but this is the general idea.

I think that was a fine solution to the problem. Why not use CGI.pm? And sure, there are many ways to tackle this problem - here is another that utilizes your ternary suggestion:

use strict;

my @ss = ('SSD','PERS','SS','CHILD SUP');
my %checked = map {$_ => 1} ('SSD','PERS');

foreach my $ss (@ss) {
   print qq|<input type="checkbox" name="ss" value="$ss"|,
      $checked{$ss} ? ' selected' : '', ">\n"
   ;
}
[download]

UPDATE:
Actually, @checked should be populated with something like the original:

my %checked = map {$_ => 1} split(/,/,$INPUT{'ss'})
[download]

But that point is moot (mu?) - use CGI.pm to handle form processing.

jeffa

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)

I think CGI.pm could do it for you, it has parameters to auto-fill in submitted values (not only checkboxes). You should read the documentation for it.

But just focusing on your code, you could simplify it a lot. First, use a subroutine. (Note that the description for a checkbox should follow the checkbox, but I made it fit your code)

    sub checkbox {
        my ($name, $value, $sel) = @_;
        my $checked = ($value eq $sel) ? "checked" : "";

        print <<EOT
    $value: <input type="checkbox" $checked name="$name" 
        value="$value">&nbsp;&nbsp;
    EOT
        return ($value eq $sel);
    }
[download]

This way, you can write your first two if statements like this:

    checkbox("ss", "ss", $ss);
    checkbox("ss", "ssd", $ss);
[download]

Next, you could replace the first three if statements by

    my $found = 0;
    CHECKBOX: foreach (ss ssd pers) {
        if (checkbox("ss", $_, $ss)) {
            $found++;
            last CHECKBOX;
        }
    }
    if (not $found) {
        # code for those checkboxes with special treatment
    }
[download]

Of course, the code could be more simplified, but I leave that as an exercise to the reader. ;-) (No, actually, you will have to do it yourself because I don't know your problem.)

foreach $ss (split /,/,$INPUT{'ss'}) { 
    print qq($ss: <input type="checkbox" name="ss" value=")
          . lc($ss) . qq(" checked>&nbsp;&nbsp;\n); 
}
[download]

-sauoq
"My two cents aren't worth a dime.";