To add and remove multiple CSS classes to an element with JavaScript, we use the classList.add and classList.remove methods.
For instance, we write
const [el] = document.getElementsByClassName("myclass");
el.classList.add("newclass");
el.classList.remove("newclass");
to select the first element with class myclass with getElementsByClassName and destructuring.
And then we call classList.add to add the newclass class to element el.
We call classList.remove to remove the newclass class from element el.
