generator-cwf-theme/generators/app/templates/src/js/addons/back-to-top.js

Generates a Drupal CWF Bootstrap base theme

(function ($) {
  $(window).scroll(function () {
    if ($(this).scrollTop() != 0) {
      $("#btt").addClass('show');
    } else {
      $("#btt").removeClass('show');
    }
  });

  $("#btt").click(function () {
    $("body,html").animate({
      scrollTop: 0
    }, 800);
  });
})(jQuery, this);