Lista klas CSS
var myElement = document.getElementById("myElementID");
myElement.classList.add("style1 style2");
myElement.classList.remove("style1 style2");
Friendly Hawk
var myElement = document.getElementById("myElementID");
myElement.classList.add("style1 style2");
myElement.classList.remove("style1 style2");// .classList method returns an array of the classes attached to the element it is called with.
document.getElementById("myDIV").classList
// It returns
// [ 'className1', 'className2', ... ]