how to make an element still active be kept active even after refresh?

I’m using this code to active Current Element. I found this code on “w3schools.com”. in this code, If I refresh, the currently active element disappears. How can the element that is still active be kept active even after refresh?.

// 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";
  });
}
/* 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;
}
<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>

Answer

I solved your problem, try this

<!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>


 var header = document.getElementById("myDIV");
 var btns = header.getElementsByClassName("btn");

for (var i = 0; i < btns.length; i++) {
     btns[i].addEventListener('click', function(e){
        var current = document.getElementsByClassName("active");
        current[0].classList.remove('active');
        this.classList.add('active');
        var array = [];
        array.push(btns);
        localStorage.setItem('element', this.innerText);
     });
}

    function setActivatedItem(){
        var item = localStorage.getItem('element');

        if(item){
            for (var a = 0; a < btns.length; a++) {
                if(btns[a].innerText == item){
                    btns[a].classList.add('active');
                }else{
                    btns[a].classList.remove('active');
                }
            }
        }
    }

    window.onload == setActivatedItem();

</script>

</body>
</html>