Customize the wordpres menu with nav walker

wp walker manu

// functions.php
class themeslug_walker_nav_menu extends Walker_Nav_Menu {

// add classes to ul sub-menus
    function start_lvl(&$output, $depth) {
        // depth dependent classes
        $indent = ( $depth > 0 ? str_repeat("\t", $depth) : '' ); // code indent
        $display_depth = ( $depth + 1); // because it counts the first submenu as 0
        $classes = array(
            'sub-menu',
            ( $display_depth % 2 ? 'menu-odd' : 'menu-even' ),
            ( $display_depth >= 2 ? 'sub-sub-menu' : '' ),
            'menu-depth-' . $display_depth
        );
        $class_names = implode(' ', $classes);

        // build html
        $output .= "\n" . $indent . '<ul class="' . $class_names . '">' . "\n";
    }

// add main/sub classes to li's and links
    function start_el(&$output, $item, $depth, $args) {
        global $wp_query;
        $indent = ( $depth > 0 ? str_repeat("\t", $depth) : '' ); // code indent
        // depth dependent classes
        $depth_classes = array(
            ( $depth == 0 ? 'main-menu-item' : 'sub-menu-item' ),
            ( $depth >= 2 ? 'sub-sub-menu-item' : '' ),
            ( $depth % 2 ? 'menu-item-odd' : 'menu-item-even' ),
            'menu-item-depth-' . $depth
        );
        $depth_class_names = esc_attr(implode(' ', $depth_classes));

        // passed classes
        $classes = empty($item->classes) ? array() : (array) $item->classes;
        $class_names = esc_attr(implode(' ', apply_filters('nav_menu_css_class', array_filter($classes), $item)));

        // build html
        $output .= $indent . '<li data-content="'.$item->title.'"  id="nav-menu-item-' . $item->ID . '" class="' . $depth_class_names . ' ' . $class_names . '">';

        // link attributes
        $attributes = !empty($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) . '"' : '';
        $attributes .= ' class="menu-link ' . ( $depth > 0 ? 'sub-menu-link' : 'main-menu-link' ) . '"';

        $item_output = sprintf('%1$s<a%2$s>%3$s%4$s%5$s</a>%6$s', $args->before, $attributes, $args->link_before, apply_filters('the_title', $item->title, $item->ID), $args->link_after, $args->after
        );

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

}
// header.php
wp_nav_menu( array(
    'theme_location'    => 'menu-1',
    'container'     => 'div',
    'container_id'      => 'top-navigation-primary',
    'conatiner_class'   => 'top-navigation',
    'menu_class'        => 'menu main-menu menu-depth-0 menu-even', 
    'echo'          => true,
    'items_wrap'        => '<ul id="%1$s" class="%2$s">%3$s</ul>',
    'depth'         => 10, 
    'walker'        => new themeslug_walker_nav_menu
) ); // thanks nick