var element = document.getElementById('element');
element.classList.add('class-1');
element.classList.add('class-2', 'class-3');
element.classList.remove('class-3');// getting the target element
var myElement = document.querySelector('#myElement');
// example for addding some-class to the element
myElement.classList.add('some-class');
// multiple classes can be added like this
myElement.classList.add('one-class', 'one-more-class');
// example for removing any class from the element
myElement.classList.remove('any-class');var someElement= document.getElementById("myElement");
someElement.className += " newclass";//add "newclass" to element (space in front is important)element.classList.add('class');
element.classList.remove('class');// This is to add a class to any html element after you store it
// in the element variable
element.classList.add("my-class-name");
// This is to remove a class from the element
element.classlist.remove("my-class-name");
const root = document.getElementsByTagName('html')[0]
root.classList.add('hide-scrollbar')