wordpress : add last class to menu item

wordpress-last-class.php

/* Add last_item class to last li in wp_nav_menu lists*/
function add_last_item_class($strHTML) {
	$intPos = strripos($strHTML,'menu-item');
	printf("%s last_item %s",
		substr($strHTML,0,$intPos),
		substr($strHTML,$intPos,strlen($strHTML))
	);
}
add_filter('wp_nav_menu','add_last_item_class');