This feature is experimental. It may be changed or removed in a future version.
This event is emitted when an AJAX request
The event is emitted on the layer that caused the request.
Also see up:fragment:aborted.
The aborted request.
The layer this request is associated with.
If this request was intended to update an existing fragment, this is that fragment's layer.
If this request was intended to open an overlay,
the associated layer is the future overlay's parent layer.
The link or form element that caused the request.