php 修改wordpress导航菜单的方法

<ul id="menu-main">
    <li><a href="#">首页</a></li>
    <li><a href="#">关于</a></li>
    <li><a href="#">联系</a></li>
    <li><a href="#">博客</a></li>
</ul>
 

<ul id="menu-main">
     <li><a href="#"><strong>首页</strong><span>Home</span></a></li>
     <li><a href="#"><strong>关于</strong><span>About</span></a></li>
     <li><a href="#"><strong>联系</strong><span>Contact</span></a></li>
     <li><a href="#"><strong>博客</strong><span>Blog</span></a></li>
</ul>
 

class description_walker extends Walker_Nav_Menu {
    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;
        $classes[] = 'menu-item-' . $item->ID;
 
        $class_names = join( ' ', apply_filters( 'nav_menu_css_class', array_filter( $classes ), $item, $args ) );
        $class_names = ' class="' . esc_attr( $class_names ) . '"';
 
        $id = apply_filters( 'nav_menu_item_id', 'menu-item-'. $item->ID, $item, $args );
        $id = strlen( $id ) ? ' id="' . esc_attr( $id ) . '"' : '';
 
        $output .= $indent . '<li' . $id . $value . $class_names .'>';
 
        $prepend = '<strong>';
        $append = '</strong>';
        $description  = ! empty( $item->attr_title ) ? '<span>' . esc_attr( $item->attr_title ) . '</span>' : '';
 
        if($depth != 0) {
            $description = $append = $prepend = "";
            $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        ) .'"' : '';
 
        $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 );
    }
}

<?php
wp_nav_menu( array('walker' => new description_walker()));
?>