Live Demo: how to add or remove class using jquery

<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.6.0/jquery.min.js"></script>
<style>
 .mystyle {
  padding: 30px;
  margin:5px;
  background-color: red;
  color:white;
  border: 1px solid green;
  font-size: 20px;
}
</style>
</head>
<body>

<p>Click the "clickme" button to remove the "mystyle" class from the div element which contain id mydiv:</p>

<button id="clickme">click me</button>

<div id="mydiv">
This is a DIV element.
</div>
<script>
 $(document).ready(function() {
   $("#clickme").click(function() {
	 if($("#mydiv").hasClass("mystyle")){
        $("#mydiv").removeClass("mystyle");
      } 
      else {
		  $("#mydiv").addClass("mystyle");
      } 
    });
});
</script>
</body>
</html>