$(document).ready(function() {

    // language selector
    $('#language_select').change(function() {
        $('#language_form').submit();
    });
    
    // registration form
    $('#id_subscription_amount').change(function() {
        if ($(this).val() > 0) {
            $('#id_payment_method_group').show();
        } else {
            $('#id_payment_method_group').hide();
        }
    });

});