sub json_run_step {
    my $self = shift;
    my $form = $self->form;
    my $type = $form->{'type'};

    my $data;
    my $ok = eval {
        die "Invalid type \"$type\"\n"   if $type !~ /^[a-z]\w+$/;
        die "Invalid method \"$type\"\n" if ! $self->can($type);
        $data = $self->$type($form);
    };
    if (! $ok) {
        $data = {
            error => "$@" || "An error occurred",
         };
    }

    $self->cgix->print_content_type('application/x-javascript');
    print JSON::to_json($data)."\n";
    return 1;
}