website/www/site/assets/js/fix-menu.js

// Licensed under the Apache License, Version 2.0 (the 'License'); you may not
// use this file except in compliance with the License. You may obtain a copy of
// the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an 'AS IS' BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations under
// the License.

$(document).ready(function() {
  function FixMenu(conf) {
    var idMenu = conf["classNameMenu"];
    var CONST = {
      DESKTOP_BREAKPOINT: 1024
    };

    return {
      "idMenu": idMenu,
      "menuConfig": {},

      "bindEvents": function() {
        var _self = this;

        $(window).scroll(function(e) {
          if($(window).width() > CONST.DESKTOP_BREAKPOINT) {
            var scroll = $(window).scrollTop();
            var scrollMenu = scroll + $("." + idMenu).height() + _self.menuConfig.offsetTop;
            var scrollHeight = scroll + $(window).height();
            var bodyHeightOffset = $('body')[0].scrollHeight - _self.menuConfig.offsetBottom;

            if (scroll <= _self.menuConfig.offsetTop) {
              $("." + idMenu).css({
                top: '',
                bottom: ''
              });
            } else if (scroll > _self.menuConfig.offsetTop && scrollMenu < bodyHeightOffset) {
              $("." + idMenu).css({
                top: _self.menuConfig.offsetTop,
                bottom: ''
              });
            } else if (scrollMenu >= bodyHeightOffset) {
              $("." + idMenu).css({
                top: '',
                bottom: scrollHeight - bodyHeightOffset
              });
            }
          } else {
            $("." + idMenu).css({
              top: '',
              bottom: ''
            });
          }
        });

        $(window).resize(function(e) {
          if($(window).width() <= CONST.DESKTOP_BREAKPOINT) {
            $("." + idMenu).css({
              top: '',
              bottom: ''
            });
          }
        });
      },
      "isMenuPresent": function () {
        return $("." + idMenu).length > 0
      },
      "init": function() {
        if (this.isMenuPresent()) {
          this.menuConfig = $("." + this.idMenu).data();
          this.bindEvents();
        }
      }
    }
  }

  FixMenu({ "classNameMenu":"page-nav" }).init();
});