JSFiddle - React, Tailwind, and code Playground

HTML

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<div class="scrollup">Click to scroll up</div>

CSS

.scrollup
{
    width: 110px;
    height: 30px;
    background: red;
    color: white;
    border-radius: 10px;
    position: fixed;
    display: none;
    right: 20px;
    top: 260px;
}

JavaScript

$(document).ready(function() {
    $(window).scroll(function(){
        if ($(window).scrollTop() > 300){
            $(".scrollup").fadeIn();
        } else {
            $(".scrollup").fadeOut();
        }
    });
});


$(document).ready(function(){
  $(".scrollup").click(function(){
    $('html, body').animate({scrollTop: '0px'}, 300);
  });
});