Accessible WordPress Navigation Menu

accessible-menu.php

<div class="menu-container">
    <button class="menu-button" aria-expanded="false" aria-controls="site-header-menu" aria-label="<?php esc_attr_e( 'Menu', 'textdomain' ); ?>"></button>
    <div id="site-header-menu" class="site-header-menu">
        <?php
        wp_nav_menu(
            array(
                'theme_location'       => 'primary',
                'container'            => 'nav',
                'container_class'      => 'main-navigation',
                'container_id'         => 'site-navigation',
                'container_aria_label' => 'Primary Menu',
            ),
        );
        ?>
    </div>
</div>

script.js

document.addEventListener('DOMContentLoaded', function () {
	// Getting main menu elements
	const menuContainer = document.querySelector('.menu-container');
	const menuToggle = menuContainer.querySelector('.menu-button');
	const siteHeaderMenu = menuContainer.querySelector('#site-header-menu');
	const siteNavigation = menuContainer.querySelector('#site-navigation');

	// If the menu toggle button exists, set up its behaviors
	if (menuToggle) {
		// Initial ARIA attribute setup for accessibility
		menuToggle.setAttribute('aria-expanded', 'false');
		siteNavigation.setAttribute('aria-expanded', 'false');

		// Event listener for main menu toggle button
		menuToggle.addEventListener('click', function () {
			// Toggle visual states for the button and menu
			this.classList.toggle('toggled-on');
			siteHeaderMenu.classList.toggle('toggled-on');

			// Determine and set the new expanded state for ARIA
			const isExpanded = this.getAttribute('aria-expanded') === 'true';
			const newExpandedState = isExpanded ? 'false' : 'true';

			// Update ARIA attributes
			this.setAttribute('aria-expanded', newExpandedState);
			siteNavigation.setAttribute('aria-expanded', newExpandedState);
		});
	}

	// Set up dropdown toggle buttons for menu items with children
	const menuItemsWithChildren = document.querySelectorAll(
		'.menu-item-has-children > a'
	);
	menuItemsWithChildren.forEach(function (item) {
		const linkText = item.textContent;

		// Create the dropdown toggle button
		const dropdownToggle = document.createElement('button');
		dropdownToggle.className = 'dropdown-toggle';
		dropdownToggle.setAttribute('aria-expanded', 'false');

		// Set ARIA label for accessibility
		dropdownToggle.setAttribute('aria-label', linkText + ' submenu');

		// Insert the dropdown button after the menu item
		item.insertAdjacentElement('afterend', dropdownToggle);

		// Set up behavior when the dropdown button is clicked
		dropdownToggle.addEventListener('click', function () {
			// Determine the expanded state of the dropdown
			const isExpanded = this.getAttribute('aria-expanded');

			// Toggle the dropdown's expanded state
			if (isExpanded === 'true') {
				this.setAttribute('aria-expanded', 'false');
			} else {
				this.setAttribute('aria-expanded', 'true');
			}
		});
	});

	// Toggle dropdowns behavior
	const dropdownToggles = siteHeaderMenu.querySelectorAll('.dropdown-toggle');
	dropdownToggles.forEach(function (toggle) {
		toggle.addEventListener('click', function (e) {
			e.preventDefault();
			e.stopPropagation(); // Prevent event from bubbling

			// Toggle the clicked dropdown
			this.classList.toggle('toggled-on');
			const nextSubMenu = this.nextElementSibling;
			if (nextSubMenu && nextSubMenu.classList.contains('sub-menu')) {
				nextSubMenu.classList.toggle('toggled-on');
			}

			// Update the ARIA expanded state of the dropdown
			const isExpanded =
				this.getAttribute('aria-expanded') === 'false'
					? 'true'
					: 'false';

			this.setAttribute('aria-expanded', isExpanded);

			// Close other dropdowns on the same level to avoid multiple open dropdowns
			const siblingToggles = Array.from(
				this.parentElement.parentElement.children
			)
				.map((el) => el.querySelector('.dropdown-toggle'))
				.filter((el) => el !== null && el !== this);

			siblingToggles.forEach((sibToggle) => {
				sibToggle.classList.remove('toggled-on');
				const sibSubMenu = sibToggle.nextElementSibling;
				if (sibSubMenu && sibSubMenu.classList.contains('sub-menu')) {
					sibSubMenu.classList.remove('toggled-on');
				}
				sibToggle.setAttribute('aria-expanded', 'false');
			});
		});
	});

	// Indicate that a menu has a sub-menu
	const subMenus = document.querySelectorAll(
		'.sub-menu .menu-item-has-children'
	);
	subMenus.forEach(function (subMenu) {
		subMenu.parentElement.classList.add('has-sub-menu');
	});

	// Keyboard navigation setup for menu
	const menuLinksAndDropdownToggles = document.querySelectorAll(
		'.menu-item a, button.dropdown-toggle'
	);
	menuLinksAndDropdownToggles.forEach(function (element) {
		element.addEventListener('keydown', function (e) {
			const key = e.keyCode;

			// Key handling for improved keyboard navigation
			if (![27, 37, 38, 39, 40].includes(key)) {
				return;
			}

			// Handle different keys for navigation
			switch (key) {
				case 27: // Escape: Close dropdown or main menu
					e.preventDefault();
					e.stopPropagation();
					const parentDropdown =
						this.closest('ul').previousElementSibling;
					if (
						parentDropdown &&
						parentDropdown.classList.contains('dropdown-toggle') &&
						parentDropdown.classList.contains('toggled-on')
					) {
						parentDropdown.focus();
						parentDropdown.click();
					} else if (!parentDropdown) {
						// If no parent dropdown found, close the main menu.
						if (
							menuToggle &&
							menuToggle.classList.contains('toggled-on')
						) {
							menuToggle.click();
							menuToggle.focus();
						}
					}
					break;

				case 37: // Left arrow: Move focus to the previous item
					e.preventDefault();
					if (this.classList.contains('dropdown-toggle')) {
						this.previousElementSibling.focus();
					} else {
						const prevSibling =
							this.parentElement.previousElementSibling;
						if (
							prevSibling &&
							prevSibling.querySelector('button.dropdown-toggle')
						) {
							prevSibling
								.querySelector('button.dropdown-toggle')
								.focus();
						} else if (
							prevSibling &&
							prevSibling.querySelector('a')
						) {
							prevSibling.querySelector('a').focus();
						}
					}
					break;

				case 39: // Right arrow: Move focus to the next item or enter a submenu
					e.preventDefault();
					if (
						this.nextElementSibling &&
						this.nextElementSibling.matches(
							'button.dropdown-toggle'
						)
					) {
						this.nextElementSibling.focus();
					} else {
						const nextSibling =
							this.parentElement.nextElementSibling;
						if (nextSibling) {
							nextSibling.querySelector('a').focus();
						}
					}
					if (
						this.matches('ul.sub-menu .dropdown-toggle.toggled-on')
					) {
						this.parentElement
							.querySelector('ul.sub-menu li:first-child a')
							.focus();
					}
					break;

				case 40: // Down arrow: Move focus to the next item or submenu
					e.preventDefault();
					if (this.nextElementSibling) {
						const firstChildLink =
							this.nextElementSibling.querySelector(
								'li:first-child a'
							);
						if (firstChildLink) {
							firstChildLink.focus();
						}
					} else {
						const nextElem = this.parentElement.nextElementSibling;
						if (nextElem) {
							nextElem.querySelector('a').focus();
						}
					}
					break;

				case 38: // Up arrow: Move focus to the previous item or exit a submenu
					e.preventDefault();
					const prevElem = this.parentElement.previousElementSibling;
					if (prevElem) {
						prevElem.querySelector('a').focus();
					} else {
						const closestUl = this.closest('ul');
						if (
							closestUl &&
							closestUl.previousElementSibling.matches(
								'.dropdown-toggle.toggled-on'
							)
						) {
							closestUl.previousElementSibling.focus();
						}
					}
					break;
			}
		});
	});
});

style.scss

.menu-container:after {
	display: table;
	clear: both;
	content: "";
}

.site-header-menu {
	display: none;
	font-size: 1rem;
	clear: both;
}

.main-navigation ul {
	margin: 0;
	padding: 0;
	list-style: none;
}

.main-navigation ul li {
	margin-right: 40px;
	margin-bottom: 10px;
	min-height: 30px;
}

.main-navigation ul a,
.main-navigation ul a:visited {
	border: none;
	color: $black;
	font-size: 16px;
	font-weight: 400;
	line-height: 22px;
	position: relative;
	text-decoration: none;
	text-transform: uppercase;
}

.main-navigation ul a:hover {
	border-bottom: 3px solid;
}

.main-navigation ul ul {
	display: none;
	margin-top: 0px;
	margin-left: 25px;
}

.main-navigation ul ul li{
	a{
		font-size: 14px;
		text-transform: none;
		padding: 0;
		margin-bottom: 10px;
		border-bottom: solid 4px transparent;
		padding-bottom: 2px;
	}
	&:last-child{
		padding-bottom: 0;
		a{
			margin-bottom: 0;
		}
	}
	&:hover > a {
		background: #EEEEEE;
	}
}

.main-navigation ul ul ul {
	display: none;
	margin-left: 25px;
}

.no-js .site-header-menu,
.site-header-menu.toggled-on {
	display: block;
}

.site-header-menu.toggled-on {
	margin-top: 10px;
}

.no-js .main-navigation ul,
.main-navigation ul .sub-menu.toggled-on {
	display: block;
}

button.dropdown-toggle,
button.menu-button {
	display: inline;
	background-color: transparent;
	border: 0;
	-webkit-appearance: none;
	-moz-appearance: none;
	cursor: pointer;
	content: "";
}

button.dropdown-toggle {
	width: 25px;
	height: 25px;
	position: absolute;
	right: 15px;
	margin-left: 10px;
	padding: 2px;
}

.dropdown-toggle:after,
.dropdown-toggle.toggled-on:after {
	font-size: 1rem;
}

.menu-button {
	width: 25px;
	height: 25px;
	float: right;
	padding: 0 !important;
	font-size: 1.35rem;
	margin-top: 25px;
	padding: 5px 5px 5px 5px;
}

.main-navigation a:focus,
button.dropdown-toggle:focus,
button.menu-button:focus {
	outline: 1px solid $black;
	outline-offset: 2px;
}

.no-js .menu-button {
	display: none;
}

/* Plus symbol to expand sub-menu on mobile */
.dropdown-toggle:after {
	content: "\002B";
}

/* Minus symbol to collapse sub-menu on mobile */
.dropdown-toggle.toggled-on:after {
	content: "\2212";
}

/* 'Hamburger' or bars to expand menu on mobile*/
.menu-button:before {
	content: "\f0c9";
	font-family: "Font Awesome 6 Free"; font-weight: 400;
}

/* Times (x) to collapse menu on mobile*/
.menu-button.toggled-on:before {
	content: "\f00d";
	font-family: "Font Awesome 6 Free"; font-weight: 400;
}

.dropdown-toggle:after,
.dropdown-toggle.toggled-on:after,
.menu-button:before,
.menu-button.toggled-on:before {
	font-weight: bold;
}

/* Screen readers */
.screen-readers {
	position: absolute !important;
	width: 1px;
	height: 1px;
	margin: -1px;
	padding: 0;
	border: 0;
	word-break: normal !important;
	overflow: hidden;
	clip: rect(0 0 0 0);
}

/* Desktop media query */
@media only screen and (min-width: 768px) {
	button.menu-button {
		display: none;
	}
	.menu-container {
		padding-top: 0;
		padding-bottom: 0;
		padding-left: 0;
	}
	.site-header-menu {
		display: block;
		margin-left: 10px;
	float: right;
	//margin-top: 30px;
	clear: none;
	}
	.main-navigation ul {
		position: relative;
		float: left;
	}
	.main-navigation ul li {
		position: relative;
		float: left;
		margin: 0;
		padding: 10px;
	min-height: 0px;
	}
	.no-js .main-navigation ul ul,
	.main-navigation ul ul {
		position: absolute;
		display: none;
		top: 100%;
		left: 0;
		padding: 0;
		z-index: 999;

	background: $white;
	border-radius: 15px;
	padding: 25px;
	}
	.no-js .main-navigation ul ul li,
	.main-navigation ul ul li {
		float: none;
		width: 175px;
		padding: 0;
		padding-bottom: 15px;
	}
	.main-navigation ul .has-sub-menu > li {
		padding-right: 40px;
	}
	.no-js .main-navigation ul ul ul,
	.main-navigation ul ul ul {
		top: -1px;
		left: 100%;
		margin-left: 0;
		margin-top: -5px;
	}
	ul.sub-menu .dropdown-toggle {
		position: absolute;
		right: 10px;
		top: 4px;
	}

	/* Arrow down */
	.main-navigation ul .dropdown-toggle:after {
		content: "\f078";
		font-family: "Font Awesome 6 Free"; font-weight: 400;
		font-size: .75rem;
	}

	/* Arrow right */
	.main-navigation ul ul .dropdown-toggle:after {
		content: "\f054";
		font-family: "Font Awesome 6 Free"; font-weight: 400;
		font-size: .75rem;
	}

	/* Arrow up */
	.main-navigation ul .dropdown-toggle.toggled-on:after {
		content: "\f077";
		font-family: "Font Awesome 6 Free"; font-weight: 400;
	}

	/* Arrow left */
	.main-navigation ul ul .dropdown-toggle.toggled-on:after {
		content: "\f053";
		font-family: "Font Awesome 6 Free"; font-weight: 400;
	}

	.main-navigation ul .dropdown-toggle:after,
	.main-navigation ul ul .dropdown-toggle:after,
	.main-navigation ul .dropdown-toggle.toggled-on:after,
	.main-navigation ul ul .dropdown-toggle.toggled-on:after {
		font-weight: bold;
	}

	button.dropdown-toggle {
		width: auto;
		height: auto;
		position: inherit;
		right: auto;
	}
	.main-navigation ul li:hover > ul {
		display: block;
	}
}

Just giving this a gentle nudge.

@joe-deltaechovictor the code has been updated.

@SteveJonesDev Legend - will give it a go shortly.

@SteveJonesDev Sorry to be a pain, but I'm still getting the same issue. I've diff'd the code and the JS looks the same as before?

Good tutorial !

Can you insert all Accessibility Features from
https://www.w3.org/WAI/ARIA/apg/patterns/menubar/examples/menubar-navigation/#accessibilityfeatures

and keyboard Support (for example with the right arrow,left arrow, home, end keys when in the submenus)
https://www.w3.org/WAI/ARIA/apg/patterns/menubar/examples/menubar-navigation/#kbd_label