code: function removeEventListener(el, eventName, handler) {
      if (window.jQuery) {
        $(el).off(eventName, handler);
      } else if (el.removeEventListener) {
        el.removeEventListener(eventName, handler);
      } else {
        el.detachEvent('on' + eventName, handler);
      }
    }
docs: Remove listener from an element (IE8 compatible)