If you’re like me and come from jQuery to pure JavaScript, these helper functions might be very helpful for you: function hasClass(el, className) { if (el.classList) return el.classList.contains(className); else return !!el.className.match(new RegExp(‘(\\s|^)’ + className + ‘(\\s|$)’)); } function addClass(el, className) { if (el.classList) el.classList.add(className); else if (!hasClass(el, className)) el.className += ” ” + className; }… Continue reading JavaScript “hasClass()”, “addClass()”, “removeClass()” helper functions