Listener manager to help track and add/remove them

addTrackedListener.js

// Link: http://www.jimmycuadra.com/posts/keeping-track-of-javascript-event-handlers/

function addTrackedListener(element, type, handler) {
  if (!element.trackedEvents) {
    element.trackedEvents = {};
  }

  if (!element.trackedEvents[type]) {
    element.trackedEvents[type] = [];

    element[type] = function () {
      for (var i = 0; i < element.trackedEvents[type].length; i++) {
        element.trackedEvents[type][i]();
      }
    };
  }

  element.trackedEvents[type].push(handler);
};