#!/usr/bin/perl

use strict;
use warnings;

use CGI;
use Encode         qw( decode );
use HTML::Entities qw( encode_entities );

my $cgi = CGI->new();

my $val = $cgi->param('key');
use Devel::Peek;
Dump($val);
$val = decode('iso-8859-15', $val) if defined($val);

print $cgi->header('text/html; charset=iso-8859-15');
binmode STDOUT, ':encoding(iso-8859-15)';

my $val_initializer = ( defined($val)
    ? sprintf(' value="%s"', encode_entities($val, '<>&"'))
    : ''
);

print(<<"__EOI__");
<title>Test</title>
<form method="POST">
<input type="text" name="key"$val_initializer>
<input type="submit">
</form>
__EOI__