sounds like what an extension could do. store in localstorage the last hour of forms. I especially hate clicking submit to get an error and an empty form again.
Ugh, a form that takes 15 minutes or more to fill out, without any feedback or other interaction, is itself a UX problem. It should at least be auto-saving.
More likely it will have a “submit” button that runs a script that blocks submission wen you missed a field. And wipes out a couple of other fields (usually passwords) so that you have to re-enter those after hitting that “submit” button again.
