sub Parse_Form {
    use CGI qw/:standard/;

    foreach my $key ( param() ) {
        my @vals = param( $key );
        if ( scalar @vals == 1 ) {
            $formdata{ $key } = $vals[0];
        } elsif ( ! @vals ) {
            $formdata{ $key } = undef;
        } else {
            # This should be adjusted as necessary.
            $formdata{ $key } = \@vals;
        }
    }
}

##</code><code>##

%formdata = map { $_, [ param( $_ ) ] } param;

##</code><code>##

my $val = $formdata{ 'foo' }->[0];

##</code><code>##

my $allowedCHARS = 'a-zA-Z0-9\!\"\#\$\%\&\'\(\)\*\+\,\-\.\/\:\;\<\=\>\?\@\[\\\]\^\_\`\{\|\}\~';

##</code><code>##

my $allowedCHARS = 'a-zA-Z0-9' . quotemeta( '!"#$%&\'()*+,-./:;<=>?@[\]^_`{|}~' );