How to Display WordPress Sub Menu Items Only for a Given Menu Item
As a WordPress developer, you may have encountered a scenario where you need to display sub menu items only for a specific primary menu item, rather than showing all submenus across your website. This can be a common requirement when building custom navigation menus or implementing complex site structures.
In this blog post, we'll dive into the step-by-step process to achieve this functionality and provide real-world examples to help you implement it on your WordPress site.
Understanding WordPress Menu Structure
Before we get started, it's important to understand the underlying structure of WordPress menus. In WordPress, the main menu structure is typically defined using the wp_nav_menu()
function, which generates an unordered list (<ul>
) of menu items.
Each menu item is represented by a list item (<li>
) element, and sub menu items are nested within their parent menu item using additional unordered list elements.
Here's an example of what the HTML structure might look like for a WordPress menu with sub menu items:
<ul id="main-menu">
<li id="menu-item-1">
<a href="#">Menu Item 1</a>
<ul class="sub-menu">
<li id="menu-item-11"><a href="#">Sub Menu Item 1</a></li>
<li id="menu-item-12"><a href="#">Sub Menu Item 2</a></li>
</ul>
</li>
<li id="menu-item-2">
<a href="#">Menu Item 2</a>
<ul class="sub-menu">
<li id="menu-item-21"><a href="#">Sub Menu Item 1</a></li>
<li id="menu-item-22"><a href="#">Sub Menu Item 2</a></li>
</ul>
</li>
</ul>
In this example, the main menu has two menu items: "Menu Item 1" and "Menu Item 2". Each of these menu items has its own sub menu items nested within an additional unordered list with the class "sub-menu".
Identifying the Target Menu Item
To display sub menu items only for a specific menu item, you'll first need to identify the target menu item. This can be done by inspecting the HTML structure of your WordPress menu, as shown in the example above.
You can use browser development tools (such as the browser's built-in developer tools or a tool like Chrome DevTools) to inspect the HTML structure of your WordPress menu and find the specific menu item you want to target.
Once you've identified the target menu item, make a note of its unique identifier, which is typically the id
attribute of the <li>
element.
Selectively Displaying Sub Menu Items
Now that you've identified the target menu item, you can use WordPress' built-in functions to selectively display the sub menu items for that specific item.
Here's an example code snippet that you can use to achieve this:
function display_submenu_for_specific_item($items, $args) {
// Define the target menu item ID
$target_menu_item_id = 'menu-item-1';
// Check if the current menu item matches the target menu item
if ($args->menu_item_id === $target_menu_item_id) {
// Display the sub menu items
return $items;
} else {
// Hide the sub menu items
return '';
}
}
add_filter('wp_nav_menu_objects', 'display_submenu_for_specific_item', 10, 2);
In this example, the display_submenu_for_specific_item()
function is a custom WordPress filter that is hooked to the wp_nav_menu_objects
filter. This filter is responsible for modifying the menu item objects before they are rendered.
The function takes two parameters:
$items
: An array of menu item objects.
$args
: An object containing various arguments related to the menu.
Inside the function, we first define the $target_menu_item_id
variable, which holds the unique identifier (typically the id
attribute) of the menu item we want to target.
Then, we check if the current menu item's id
matches the $target_menu_item_id
. If it does, we return the $items
array, which will display the sub menu items. If the current menu item doesn't match the target, we return an empty string, effectively hiding the sub menu items.
By using this approach, you can selectively display sub menu items only for the specific menu item you've targeted.
Real-World Example
Let's consider a more practical example to better understand how this works.
Imagine you have a WordPress website with a main navigation menu that includes the following items:
- Home
- About
- Services
- Web Development
- Graphic Design
- Digital Marketing
- Contact
In this scenario, you only want to display the sub menu items (Web Development, Graphic Design, and Digital Marketing) when the "Services" menu item is selected, and hide the sub menu items for all other main menu items.
Here's how you can implement this using the code snippet from the previous section:
function display_submenu_for_specific_item($items, $args) {
// Define the target menu item ID
$target_menu_item_id = 'menu-item-3';
// Check if the current menu item matches the target menu item
if ($args->menu_item_id === $target_menu_item_id) {
// Display the sub menu items
return $items;
} else {
// Hide the sub menu items
return '';
}
}
add_filter('wp_nav_menu_objects', 'display_submenu_for_specific_item', 10, 2);
In this example, the $target_menu_item_id
is set to 'menu-item-3'
, which corresponds to the "Services" menu item in the main navigation menu.
When the user navigates to the "Services" page or selects the "Services" menu item, the display_submenu_for_specific_item()
function will be called, and it will check if the current menu item matches the $target_menu_item_id
. Since they match, the function will return the $items
array, effectively displaying the sub menu items (Web Development, Graphic Design, and Digital Marketing).
On the other hand, when the user navigates to any other page or selects any other menu item, the function will return an empty string, hiding the sub menu items.
Improved Usability with Conditional Statements
To further enhance the user experience, you can add some conditional statements to the display_submenu_for_specific_item()
function to handle additional scenarios.
For example, you might want to display the sub menu items even when the user is on a sub-page of the "Services" section, or you might want to handle cases where the menu structure changes in the future.
Here's an example of how you can modify the function to handle these additional scenarios:
function display_submenu_for_specific_item($items, $args) {
// Define the target menu item ID
$target_menu_item_id = 'menu-item-3';
// Get the current page ID
$current_page_id = get_the_ID();
// Check if the current menu item matches the target menu item or if the current page is a child of the target menu item
if ($args->menu_item_id === $target_menu_item_id || in_array($current_page_id, get_post_ancestors($target_menu_item_id))) {
// Display the sub menu items
return $items;
} else {
// Hide the sub menu items
return '';
}
}
add_filter('wp_nav_menu_objects', 'display_submenu_for_specific_item', 10, 2);
In this updated example, we've added a check to see if the current page ID is a child of the target menu item. This is done using the get_post_ancestors()
function, which returns an array of parent page IDs for the current page.
By incorporating this additional check, the sub menu items will now be displayed not only when the "Services" menu item is selected, but also when the user is on a sub-page within the "Services" section of the website.
This approach provides a more seamless and intuitive user experience, as users will always see the relevant sub menu items regardless of their current location within the website.
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Conclusion
Selectively displaying sub menu items for a specific WordPress menu item can be a powerful technique to enhance the navigation and user experience of your website. By understanding the underlying menu structure and utilizing WordPress' built-in functions, you can easily implement this functionality and ensure that your users always have access to the most relevant sub menu items.
Remember, the key to successful implementation is to thoroughly test your code and ensure that it works as expected across different scenarios and menu configurations. Additionally, consider periodically reviewing and updating your code to adapt to any changes in the WordPress core or your website's structure.
By following the steps outlined in this article, you can take control of your WordPress menu structure and provide a more intuitive and user-friendly navigation experience for your website visitors.
Flowpoint.ai can help you identify all the technical errors that are impacting conversion rates on your WordPress website and directly generate recommendations to fix them, including issues with your menu structure and navigation.