Redmine

<div id="us-btn-up"><span class="chevron-up"></span></div>

function setupUpButton() {

  $(window).scroll(function() {

    if ($(this).scrollTop() > 30) {

      $('#us-btn-up').addClass('showed');

    } else {

      $('#us-btn-up').removeClass('showed');

    }

  });

  $('#us-btn-up').click(function () {

    $('html, body').animate({ scrollTop: 0 }, 300);

  });

}

$(document).ready(setupUpButton);

#us-btn-up {

  display: none;

}

@media all and (min-width: 900px) {

  #us-btn-up {

    display: block;

    height: 0;

    padding: 0;

    overflow: hidden;

    position: fixed;

    bottom: 35px;

    right: 35px;

    z-index: 99;

    border: none;

    outline: none;

    color: #888;

    cursor: pointer;

    border-radius: 4px;

    transition: opacity .3s, background-color .3s;

    opacity: 0;

    box-shadow: 0 2px 2px 0 rgba(0, 0, 0, 0.14), 0 1px 5px 0 rgba(0, 0, 0, 0.12), 0 3px 1px -2px rgba(0, 0, 0, 0.2), 0 0 30px 0 rgba(0, 0, 0, 0.15) inset;

    background: #fff;

  }

  #us-btn-up.showed {

    height: auto;

    opacity: 0.7;

    padding: 15px 20px;

  }

  #us-btn-up:hover {

    background-color: #f5f5f5;

  }

  .chevron-up {

    position: relative;

    height: 16px;

    width: 16px;

    top: 1px;

    display: inline-block;

    background-image: url(../images/chevron-up.png);

    background-size: cover;

    margin: 0;

    -webkit-font-smoothing: antialiased;

    -moz-osx-font-smoothing: grayscale;

  }

}

# frozen_string_literal: true

# Redmine - project management software

# Copyright (C) 2006-2022  Jean-Philippe Lang

#

# This program is free software; you can redistribute it and/or

# modify it under the terms of the GNU General Public License

# as published by the Free Software Foundation; either version 2

# of the License, or (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

require File.expand_path('../../application_system_test_case', __FILE__)

class ScrollToTopButtonTest < ApplicationSystemTestCase

  fixtures :issues, :users, :projects, :trackers, :projects_trackers, :issue_statuses, :enumerations, :projects_trackers,

           :roles, :members, :member_roles, :enabled_modules

  def setup

    super

    100.times { Issue.generate! }

  end

  def test_scroll_button

    log_user('admin', 'admin')

    visit '/issues?per_page=100'

    # scroll to the page bottom

    page.execute_script "window.scrollBy(0,10000)"

    # button appears

    assert has_css? '#us-btn-up.showed'

    # scroll back to the top

    find('div#us-btn-up').click

    # no button

    assert has_no_css? '#us-btn-up.showed'

  end

end