JavaScript CSS how to add and remove multiple CSS classes to an element

Question

How can assign multiple css classes to an html element through javascript without using any libraries?

Answer 1

Try this:

function addClass(element, value) {
  if(!element.className) {
    element.className = value;
  } else {
    newClassName = element.className;
    newClassName+= " ";
    newClassName+= value;
    element.className = newClassName;
  }
}

Similar logic could be used to make a removeClass function.