code: function addEvent(el, e, callback, capture) {
      if (el.addEventListener) {
        el.addEventListener(e, callback, capture || false);
      }
      else
        if (el.attachEvent) {
          el.attachEvent('on' + e, callback);
        }
    }
docs: Adds eventlisteners cross browser
  @param {Object}   el       The element which gets the listener
  @param {String}   e        The event type
  @param {Function} callback The action to execute on event
  @param {Boolean}  capture      The capture mode