https://www.coeurdecharente.fr/wp-content/themes/pays-manslois/js/ui.js

1(function (window, document) {
2
3    var layout   = document.getElementById('layout'),
4        menu     = document.getElementById('menu'),
5        menuLink = document.getElementById('menuLink');
6
7    function toggleClass(element, className) {
8        var classes = element.className.split(/\s+/),
9            length = classes.length,
10            i = 0;
11
12        for(; i < length; i++) {
13          if (classes[i] === className) {
14            classes.splice(i, 1);
15            break;
16          }
17        }
18        // The className is not found
19        if (length === classes.length) {
20            classes.push(className);
21        }
22
23        element.className = classes.join(' ');
24    }
25
26    menuLink.onclick = function (e) {
27        var active = 'active';
28
29        e.preventDefault();
30        toggleClass(layout, active);
31        toggleClass(menu, active);
32        toggleClass(menuLink, active);
33    };
34
35}(this, this.document));