Technically, yes. It can be done... but I don't recommend it. The script needs to constantly evaluate the length of the fields and recalculate where the text needs to go. It's essentially impossible to create something that works as well as a word processor.
Instead, consider capturing all of the text in a dialog box and then populating the fields, breaking the text into chunks as appropriate. To exit the text, clicking the field would reopen the dialog and allow the user to type normally. Closing the dialog again would re-chunk the text.
I wasn't aware that dialog boxes were available in Adobe Forms. That is a much better alternative! Just out of curiosity, what problems would a form have if it were created like a word processor, aside from it possibly being slow to work through since it'll constantly be recalculating text?
I'm not sure where to even start on the problems...
- Inserting text is pretty easy but maintaining the insertion point after a deletion can be problematic.
- You can't select text across the break.
- Depending on where your fields are, you can get a lot of page jumping as your edits force the content to "reflow".
At best, it's a truly horrid experience.