It would be great if a Gravity Form could be completed offline, i know theres another well known brand that has this functionallity so it should be possible?
Since GF is an add-on to a website and for saving the data + processing the related actions an internet connection is needed. While it’s absolutely possible to save the fields to cookies through JS, it wouldn’t be possible to submit the form while offline.
If you’re looking for something to save field-data in a cookie through JS,
js-cookie might be helpful: