Adding extra classes to wp_nav_menu - part 4

modified_classes.php

<?php
function display_nav_menu_items( $items, $args ) {
    foreach ($items as $item) {
        if( $item->current ) {
            $item->classes[] = 'active';
        }
    }
    return $items;
}

add_filter( 'wp_nav_menu_objects', 'display_nav_menu_items', 10, 2 );

?>