add class to an element js code example
Example 1: js add class
var element = document.getElementById('element');
element.classList.add('class-1');
element.classList.add('class-2', 'class-3');
element.classList.remove('class-3');
Example 2: js add class
var myElement = document.querySelector('#myElement');
myElement.classList.add('some-class');
myElement.classList.add('one-class', 'one-more-class');
myElement.classList.remove('any-class');
Example 3: javascript add class to element
var someElement= document.getElementById("myElement");
someElement.className += " newclass";