File: public/public/assets/frontend/js/frontend-main.js

$(document).ready(function () {
  /**
   * Scroll To Top Action
   */
  // declare variable
  var scrollTop = $(".scrollTop");
  $(scrollTop).css("opacity", "0");

  $(window).scroll(function () {
    // declare variable
    var topPos = $(this).scrollTop();

    // if user scrolls down - show scroll to top button
    if (topPos > 100) {
      $(scrollTop).css("opacity", "1");
    } else {
      $(scrollTop).css("opacity", "0");
    }
  }); // scroll END

  //Click event to scroll to top
  $(scrollTop).click(function () {
    $("html, body").animate(
      {
        scrollTop: 0,
      },
      800
    );
    return false;
  }); // click() scroll top EMD
});