how to check element has class in javascript code example

Example 1: javascript check if element has class

if(document.getElementById("myElmentID").classList.contains("hidden")){
// I have the 'hidden' class
}

Example 2: how to check has class name in js?

element.classList.contains(className);Code language: CSS (css)

Example 3: check if a class exists javascript

<div id="box" class="active"></div>