zig Tryit Editor

<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
/* Style the buttons */
.btn {
  border: none;
  outline: none;
  padding: 10px 16px;
  background-color: #f1f1f1;
  cursor: pointer;
  font-size: 18px;
}
/* Style the active class, and buttons on mouse-over */
.active, .btn:hover {
  background-color: #666;
  color: white;
}
</style>
</head>
<body>
<h1>Active Button</h1>
<p>Highlight the active/current (pressed) button.</p>
<div id="myDIV">
  <button class="btn">1</button>
  <button class="btn active">2</button>
  <button class="btn">3</button>
  <button class="btn">4</button>
  <button class="btn">5</button>
</div>
<script>
  // Add active class to the current button (highlight it)
  var header = document.getElementById("myDIV");
  var btns = header.getElementsByClassName("btn");
  for (var i = 0; i < btns.length; i++) {
    btns[i].addEventListener("click", function () {
      var current = document.getElementsByClassName("active");
      current[0].className = current[0].className.replace(" active", "");
      this.className += " active";
    });
  }
</script>
</body>

</html>