$('.click-class').click(function() {
$('.class-toggle').toggle();
$('.class-toggle').toggleClass('add-class');
})
/* var or const followed by its name */.getElementById(/* HTML element ID */);
/* var or const's name */.classList.toggle(/* Name of CSS class */);
// I hope this helps!
element.classList.toggle('class');
var menu = document.querySelector('.menu') // Using a class instead, see note below.
menu.classList.toggle('hidden-phone');