Apollo Add/Remove

script.js

btn.addEventListener('click', function (e) {
  apollo.toggleClass(divTest, 'is-hidden is-visible');
}, false);
 
document.getElementById('btn').addEventListener('click', function (e) {
  apollo.toggleClass(document.getElementById('divTest'), 'is-hidden is-visible');
}, false);

// Class Name Multiple

document.getElementById('case-study-btn').addEventListener('click', function (e) {
    var x = document.getElementsByClassName('name');
    for (var i = 0; i < x.length; i++)
        apollo.toggleClass(x[i], 'is-hidden is-visible');
}, false);

// Data Attribute Multiple

document.getElementById('case-study-btn').addEventListener('click', function (e) {
var x = document.querySelectorAll('[data-name="name"]');
    for (var i = 0; i < x.length; i++)
        apollo.toggleClass(x[i], 'is-hidden is-visible');
}, false);

/* Homework*/

document.getElementById('case-study-btn').addEventListener('click', function (e) {
apollo.toggleClass(e.target, 'js-active js-inactive');
//
var y = document.querySelectorAll('[data-post="case-study"]');
for (var i = 0; i < y.length; i++)
apollo.toggleClass(y[i], 'is-hidden is-visible');
}, false);