/** * 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; } } } )();