https://ma.tt/blog-content/themes/ma.tt/js/base-functions.js?ver=7.2-alpha-63910

1/**
2 * Reimplements functionality specific to the base theme, Twenty Thirteen, without jQuery.
3 * Does not fully reimplement everything, just the portions relevant to the ma.tt theme.
4 */
5
6( function () {
7	'use strict';
8
9	const nav = document.querySelector( '#site-navigation' );
10	const button = nav && nav.querySelector( '.menu-toggle' );
11	const menu = nav && nav.querySelector( '.nav-menu' );
12
13	/**
14	 * Enables menu toggle for small screens.
15	 */
16	( function () {
17		if ( ! nav || ! button ) {
18			return;
19		}
20
21		// Hide button if menu is missing or empty.
22		if ( ! menu || menu.childElementCount === 0 ) {
23			button.style.display = 'none';
24			return;
25		}
26
27		button.addEventListener( 'click', () => {
28			nav.classList.toggle( 'toggled-on' );
29			if ( nav.classList.contains( 'toggled-on' ) ) {
30				button.setAttribute( 'aria-expanded', 'true' );
31				menu.setAttribute( 'aria-expanded', 'true' );
32			} else {
33				button.setAttribute( 'aria-expanded', 'false' );
34				menu.setAttribute( 'aria-expanded', 'false' );
35			}
36		} );
37
38		// Fix sub-menus for touch devices.
39		if ( 'ontouchstart' in window ) {
40			const childLinks = menu.querySelectorAll(
41				'.menu-item-has-children > a, .page_item_has_children > a'
42			);
43			childLinks.forEach( ( childLink ) => {
44				childLink.addEventListener( 'click', ( e ) => {
45					const el = childLink.closest( 'li' );
46
47					if ( el && ! el.classList.contains( 'focus' ) ) {
48						e.preventDefault();
49						el.classList.add( 'focus' );
50						el.parentElement.children.forEach( ( sibling ) => {
51							if ( sibling !== el ) {
52								sibling.classList.remove( 'focus' );
53							}
54						} );
55					}
56				} );
57			} );
58		}
59
60		// Better focus for hidden submenu items for accessibility.
61		const links = menu.querySelectorAll( 'a' );
62		links.forEach( ( link ) => {
63			const handleFocusChange = () => {
64				link.closest( '.menu-item, .page_item' ).classList.toggle( 'focus' );
65			};
66			link.addEventListener( 'focus', handleFocusChange );
67			link.addEventListener( 'blur', handleFocusChange );
68		} );
69	} )();
70
71	/**
72	 * Add or remove ARIA attributes.
73	 */
74	function onResizeARIA() {
75		if ( 643 > window.innerWidth ) {
76			button.setAttribute( 'aria-expanded', 'false' );
77			menu.setAttribute( 'aria-expanded', 'false' );
78			button.setAttribute( 'aria-controls', 'primary-menu' );
79		} else {
80			button.removeAttribute( 'aria-expanded' );
81			menu.removeAttribute( 'aria-expanded' );
82			button.removeAttribute( 'aria-controls' );
83		}
84	}
85
86	window.addEventListener( 'load', onResizeARIA );
87	window.addEventListener( 'resize', onResizeARIA );
88} )();