It's not possible within the VM, but it would be possible to set up a second program to watch for the VM to create data files, and then perform some custom JS after that. That is how "This is a Real Thing that Happened" works:
http://cvaneseltine.itch.io/realthing You could ask the authors for more info.
Hopefully soon Vorple will support Quixe to allow this much more easily.