Require Us Phone Number Format

/**

 * This snippet shows how to alter the phone field so

 * that it only accepts a number between 8 and 12 digits

 * long, with an optional + at the start.

 *

 * However, this example more generally shows how you can

 * force a field value to match a certain regex pattern.

 *

 * @param  array $fields The fields in the form.

 * @return array

 */

function ed_require_us_phone_format( $fields ) {

	/* If a phone field doesn't exist, stop right here. */

	if ( ! array_key_exists( 'phone', $fields ) ) {

		return $fields;

	}

	/* Make sure that 'attrs' exists in the field. */

	if ( ! array_key_exists( 'attrs', $fields['phone'] ) ) {

		$fields['phone']['attrs'] = [];

	}

	/**

	 * This defines the format of the phone number as being a

	 * string of 3 numbers, followed by a dash, then 3 more numbers,

	 * than 4 more numbers. US phone format, required by Authorize.Net.

	 */

	$pattern = '+?[0-9]{3}-[0-9]{3}-[0-9]{4}';

	/**

	 * Add the pattern to the field by adding it to the

	 * `attrs` array.

	 */

	$fields['phone']['attrs']['pattern'] = $pattern;

	$fields['phone']['help'] = 'Please enter a phone number formatted like 111-111-1111.';

	return $fields;

}

add_filter( 'charitable_donation_form_user_fields', 'ed_require_us_phone_format' );

add_filter( 'charitable_user_address_fields', 'ed_require_us_phone_format' );

add_filter( 'charitable_campaign_submission_user_fields', 'ed_require_us_phone_format' );