Validate an additional field

Hello,

All the additional fields are passed with all the prerequisites validations. If you need custom validation or validation for your customly created field, you can use this action hook user_registration_validate_{field_key}. For example the following codes will validate the number below 10.

function ur_validate_number( $field, $form_data, $filter_hook, $form_id ) {
    $field_label          = isset( $form_data->label ) ? $form_data->label : '';
    $value                = isset( $form_data->value ) ? $form_data->value : '';

    if( $value < 10 ) {
	add_filter( $filter_hook, function ( $msg ) use ( $field_label ) {
		return __( $field_label . ' must be greater than 10.', 'user-registration' );
	});
     }
}
add_action( 'user_registration_validate_number', 'ur_validate_number', 10, 4 );