javascript to change an element's class

Browsing the web,  I find a good page that summarys ways to change a html element's class.

we can just do :

document.getElementById("myELement").classList.add("myclass");

document.getElementById("myELement").classList.remove("myclass");

if(document.getElementById("myElement")).classList.contain("myclass")

document.getElementById("myELement").classList.toggle('myclass');

To change all classes for an element:

document.getELementById('myELement').className = 'myClass';

To add an additional class to an element:

document.getElementById('myELement').className += 'myClass';

To remove a class from an element:

document.getElementById('myElement').className =document.getElementById('myElement').className.replace(/(?:^|\s)MyClass(?!\S)/g , '');