How do we target elements using their classes?

How would we change the first element with the class “MENUmenu”.

var Elements = document.getElementsByClassName("MENUmenu");
var Menu = Elements[0];
Menu.innerHTML = "We got to target this element";

This would require some HTML with a class like this:

<html>
<body>
<p>Some example HTML</p>
<div class="MENUmenu"></div>
</body>
</html>