classname toggle js

1document.getElementById('myButton').onclick = function() {
2    this.classList.toggle('active');
3}

1/* var or const followed by its name */.getElementById(/* HTML element ID */);
2/* var or const's name */.classList.toggle(/* Name of CSS class */);
3// I hope this helps! 

1document.getElementById('myButton').onclick = function() {
2
3    var className = ' ' + myButton.className + ' ';
4
5    if ( ~className.indexOf(' active ') ) {
6        this.className = className.replace(' active ', ' ');
7    } else {
8        this.className += ' active';
9    }              
10}