How can I add and remove an active class to an element in pure JavaScript

Question

I am trying to make a navigation menu I did all the HTML and CSS when come to javascript I am struck in the middle I am able to add a class to the

Answer 1

Below should help.

//Remove all classes by ID
document.getElementById("elementIdHere").className = "";
//If you wish to keep some classes on the element, use below
document.getElementById("elementIdHere").className = "keepClass";