How can I check in JavaScript if a DOM element contains a class?

Question

How can I check in JavaScript if a DOM element contains a class?

I tried the following code, but for some reason it doesn\'t work...

if (document.get         


        

Answer 1

toggleClass on element

var el = document.getElementById('element');
el.classList[['add','remove'][+el.classList.contains('class_one')]]('class_one');

or

el.classList.toggle('class_one');