1 files changed, 112 insertions, 0 deletions
diff --git a/src/js/navigation.js b/src/js/navigation.js
new file mode 100644
index 0000000..6cc0af9
--- /dev/null
+++ b/src/js/navigation.js
@@ -0,0 +1,112 @@
+/**
+ * File navigation.js.
+ *
+ * Handles toggling the navigation menu for small screens and enables TAB key
+ * navigation support for dropdown menus.
+ */
+( function() {
+	var container, button, menu, links, subMenus, i, len;
+
+	container = document.getElementById( 'site-navigation' );
+	if ( ! container ) {
+		return;
+	}
+
+	button = container.getElementsByTagName( 'button' )[0];
+	if ( 'undefined' === typeof button ) {
+		return;
+	}
+
+	menu = container.getElementsByTagName( 'ul' )[0];
+
+	// Hide menu toggle button if menu is empty and return early.
+	if ( 'undefined' === typeof menu ) {
+		button.style.display = 'none';
+		return;
+	}
+
+	menu.setAttribute( 'aria-expanded', 'false' );
+	if ( -1 === menu.className.indexOf( 'nav-menu' ) ) {
+		menu.className += ' nav-menu';
+	}
+
+	button.onclick = function() {
+		if ( -1 !== container.className.indexOf( 'toggled' ) ) {
+			container.className = container.className.replace( ' toggled', '' );
+			button.setAttribute( 'aria-expanded', 'false' );
+			menu.setAttribute( 'aria-expanded', 'false' );
+		} else {
+			container.className += ' toggled';
+			button.setAttribute( 'aria-expanded', 'true' );
+			menu.setAttribute( 'aria-expanded', 'true' );
+		}
+	};
+
+	// Get all the link elements within the menu.
+	links    = menu.getElementsByTagName( 'a' );
+	subMenus = menu.getElementsByTagName( 'ul' );
+
+	// Set menu items with submenus to aria-haspopup="true".
+	for ( i = 0, len = subMenus.length; i < len; i++ ) {
+		subMenus[i].parentNode.setAttribute( 'aria-haspopup', 'true' );
+	}
+
+	// Each time a menu link is focused or blurred, toggle focus.
+	for ( i = 0, len = links.length; i < len; i++ ) {
+		links[i].addEventListener( 'focus', toggleFocus, true );
+		links[i].addEventListener( 'blur', toggleFocus, true );
+	}
+
+	/**
+	 * Sets or removes .focus class on an element.
+	 */
+	function toggleFocus() {
+		var self = this;
+
+		// Move up through the ancestors of the current link until we hit .nav-menu.
+		while ( -1 === self.className.indexOf( 'nav-menu' ) ) {
+
+			// On li elements toggle the class .focus.
+			if ( 'li' === self.tagName.toLowerCase() ) {
+				if ( -1 !== self.className.indexOf( 'focus' ) ) {
+					self.className = self.className.replace( ' focus', '' );
+				} else {
+					self.className += ' focus';
+				}
+			}
+
+			self = self.parentElement;
+		}
+	}
+
+	/**
+	 * Toggles `focus` class to allow submenu access on tablets.
+	 */
+	( function( container ) {
+		var touchStartFn, i,
+			parentLink = container.querySelectorAll( '.menu-item-has-children > a, .page_item_has_children > a' );
+
+		if ( 'ontouchstart' in window ) {
+			touchStartFn = function( e ) {
+				var menuItem = this.parentNode, i;
+
+				if ( ! menuItem.classList.contains( 'focus' ) ) {
+					e.preventDefault();
+					for ( i = 0; i < menuItem.parentNode.children.length; ++i ) {
+						if ( menuItem === menuItem.parentNode.children[i] ) {
+							continue;
+						}
+						menuItem.parentNode.children[i].classList.remove( 'focus' );
+					}
+					menuItem.classList.add( 'focus' );
+				} else {
+					menuItem.classList.remove( 'focus' );
+				}
+			};
+
+			for ( i = 0; i < parentLink.length; ++i ) {
+				parentLink[i].addEventListener( 'touchstart', touchStartFn, false );
+			}
+		}
+	}( container ) );
+} )();