Add Class using className

/**
 * We can first create an element
 * than add class to it
 * */
 
 let el = document.createElement("div");
 el.className = "example-class";
 console.log(el);
 
 //Result:
 //<div class="example-class"></div>
 
 /**
  * We can use the same technique
  * to add a class to existing
  * element in the DOM
  * */
  
  let el = document.getElementById("el");
  el.className = "example-class";
  console.log(el);
  
  //Result:
  //<div id="el" class="example-class"></div>