sub parse_form_data
{
    local (*FORM_DATA) = @_;

    local ($request_method, $query_string, @key_value_pairs,
           $key_value, $key, $value);

    $request_method = $ENV{'REQUEST_METHOD'};

    if ($request_method eq "GET") {
        $query_string = $ENV{'QUERY_STRING'};
    } elsif ($request_method eq "POST") {
        read (STDIN, $query_string, $ENV{'CONTENT_LENGTH'});
    } else {
        &return_error (500, "Server Error",
                       "Server uses unsupported method");
    }

    @key_value_pairs = split (/&/, $query_string);

    foreach $key_value (@key_value_pairs) {
        ($key, $value) = split (/=/, $key_value);
        $value =~ tr/+/ /;
        $value =~ s/%([\dA-Fa-f][\dA-Fa-f])/pack ("C", hex ($1))/eg;

        if (defined($FORM_DATA{$key})) {
            $FORM_DATA{$key} = join ("\0", $FORM_DATA{$key}, $value);
        } else {
            $FORM_DATA{$key} = $value;
        }
    }
}

##</code><code>##

#!/usr/local/bin/perl

&parse_form_data (*simple_form);

print "Content-type: text/plain", "\n\n";
$address = $simple_form{'address'};
if ($address) {
    print "Your Address is ", $simple_form{'address'}, ".", "\n";
    print "Please visit this Web server again!", "\n";
} else {
    print "You did not enter a address.", "\n";
    print "But, you are welcome to visit this Web server again!", "\n";
}
exit(0);