Remove a class from HTML element

Use Element.classList and DOMTokenList.remove() to remove the specified class from the element.

const removeClass = (el, className) => el.classList.remove(className);

// EXAMPLE
removeClass(document.querySelector('p.special'), 'special');
// The paragraph will not have the 'special' class anymore

Source

https://www.30secondsofcode.org/js/s/remove-class