<img src="/cgi-bin/captcha/generate.pl">
generieren und mittels
<form action="cgi-bin/captcha/bsp.pl" method="post">
<input type="text" name="code" size="5">
<input type="submit">
</form>
[...]
my $code = param('code');
$stat = system("/www/www/cgi-bin/captcha/check.pl $code");
if ($stat == 0) {
[...]
} else {
[...]
}