<i class="fas fa-chevron-circle-up" onclick="topFunction()" id="kltop" title="Go to top"></i>
<script>
    //Get the button:
mybutton = document.getElementById("kltop");
// When the user scrolls down 20px from the top of the document, show the button
window.onscroll = function() {scrollFunction()};
function scrollFunction() {
  if (document.body.scrollTop > 20 || document.documentElement.scrollTop > 20) {
    mybutton.style.display = "block";
  } else {
    mybutton.style.display = "none";
  }
}
// When the user clicks on the button, scroll to the top of the document
function topFunction() {
  document.body.scrollTop = 0; // For Safari
  document.documentElement.scrollTop = 0; // For Chrome, Firefox, IE and Opera
}
</script>