Wordpress Custom nav menu

Custom Nav menu

class description_walker extends Walker_Nav_Menu {

//http://www.kriesi.at/archives/improve-your-wordpress-navigation-menu-output

    function start_el(&$output, $item, $depth, $args) {
        global $wp_query;
        $indent = ( $depth ) ? str_repeat("\t", $depth) : '';

        $class_names = $value = '';

        $classes = empty($item->classes) ? array() : (array) $item->classes;

        $class_names = join(' ', apply_filters('nav_menu_css_class', array_filter($classes), $item));
        $class_names = ' class="' . esc_attr($class_names) . '"';

        $output .= $indent . '<li id="menu-item-' . $item->ID . '"' . $value . $class_names . '>';

        $attributes = !empty($item->attr_title) ? ' title="' . esc_attr($item->attr_title) . '"' : '';
        $attributes .=!empty($item->target) ? ' target="' . esc_attr($item->target) . '"' : '';
        $attributes .=!empty($item->xfn) ? ' rel="' . esc_attr($item->xfn) . '"' : '';
        $attributes .=!empty($item->url) ? ' href="' . esc_attr($item->url) . '"' : '';

        $prepend = '<strong>';
        $append = '</strong>';
        $description = !empty($item->description) ? '<span>' . esc_attr($item->description) . '</span>' : '';

        if ($depth != 0) {
            $description = $append = $prepend = "";
        }

        $item_output = $args->before;
        $item_output .= '<a' . $attributes . '>';
        $item_output .= $args->link_before . $prepend . apply_filters('the_title', $item->title, $item->ID) . $append;
        $item_output .= $description . $args->link_after;
        $item_output .= '</a>';
        $item_output .= $args->after;

        $output .= apply_filters('walker_nav_menu_start_el', $item_output, $item, $depth, $args);
    }

}

gistfile1.txt

wp_nav_menu( array(
 'container' =>false,
 'menu_class' => 'nav',
 'echo' => true,
 'before' => '',
 'after' => '',
 'link_before' => '',
 'link_after' => '',
 'depth' => 0,
 'walker' => new description_walker())
 );