CSS

how to add active class to current element javascript

<script>
  function func(){
   document.getElementById('div').classList.add('active');
  }
</script>

<button onclick='func()'>Click</button>
<div id="div">
  This element gets 'active' class.
</div>

Adding active Class with JavaScript

$("#navMenus").on('click','li',function(){
     $(this).addClass("active");  // adding active class
});