Create new field type

field-phone.php

<?php
/**
 * This class defines new "phone" field type for Meta Box class
 * 
 * @author Tran Ngoc Tuan Anh <rilwis@gmail.com>
 * @package Meta Box
 * @see http://metabox.io/?post_type=docs&p=390
 */
if ( class_exists( 'RWMB_Field' ) )
{
	class RWMB_Phone_Field extends RWMB_Field
	{
		/**
		 * Get field HTML
		 *
		 * @param mixed $meta
		 * @param array $field
		 *
		 * @return string
		 */
		static public function html( $meta, $field )
		{
			return sprintf(
				'<input type="tel" name="%s" id="%s" value="%s" pattern="\d{3}-\d{4}">',
				$field['field_name'],
				$field['id'],
				$meta
			);
		}
	}
}