Joomla RSForm!Pro customvalidation

customvalidation.php

<?php

defined('_JEXEC') or die('Restricted access');

require_once dirname(__FILE__) . '/validation.php';

class RSFormProCustomValidations extends RSFormProValidations
{

	public static function Nederlands_Telefoonnummer($value, $extra = null, $data = null)
	{
		// The following makes sure the submitted value is a Dutch Phone Number
		if (self::validate_phonenumber($value))
		{
			// Return true if the validation passed.
			return true;
		}
		else
		{
			// Return false if the validation didn't pass.
			return false;
		}
	}

	public static function Nederlands_postcode($value, $extra = null, $data = null)
	{
		// The following makes sure the submitted value is a Dutch Postal Code
		if (self::validate_zipcode($value))
		{
			// Return true if the validation passed.
			return true;
		}
		else
		{
			// Return false if the validation didn't pass.
			return false;
		}
	}

	public static function validate_phonenumber($phonenumber) {
		return preg_match('/(^\+[0-9]{2}|^\+[0-9]{2}\(0\)|^\(\+[0-9]{2}\)\(0\)|^00[0-9]{2}|^0)([0-9]{9}$|[0-9\-\s]{10}$)/', $phonenumber);
	}

	public static function validate_zipcode($zipcode) {
		return preg_match('/^[1-9][0-9]{3}\s?[a-zA-Z]{2}$/', $zipcode);
	}
}