Section Subnav

This is a simple plugin that was born out of working on several projects with sectional navigations. For example, consider the following common navigation tree structure:

• Home
• Item
• About Us
  • Sub-item #1
  • Sub-item #2
• Item
• Item

Then, whenever on the “About Us” page or any of its sub-items, it would output that peice of the navigation:

• About Us
  • Sub-item #1
  • Sub-item #2

This is particularly useful for websites that have a top horizontal navigation which shows top-level items and want to show a vertical subnavigation in the sidebar.

This plugin works by parsing the output of the wp_nav_menu function as XML and analyzing the CSS class hooks (current-menu-ancestor, current-menu-item, and current-menu-parent). Because it uses PHP’s SimpleXML library it therefore requires PHP 5+. It uses the theme’s registered menu locations.

This plugin also exposes the section_subnav() function for theme developers to use as a template tag to manually place a subnav inside the theme. Here is the usage:

<?php

    section_subnav( array( // defaults
        'before_widget' => '<nav id="section-subnav" class="widget widget_section-subnav">',
        'after_widget' => "</nav>",
        'before_title' => '<h3 class="section-subnav-title widget-title">',
        'after_title' => '</h3>',
        'echo' => true
    ));

?>

It returns false when there is no subnavigation.

This function also provides the section_subnav_args filter hook for writing less code and easier integration with other plugins and child themes.