That book is riddled with nonsense. If you are a beginner, then do not trust anything in it.
If you want to learn something about scripting PDF forms in Acrobat, then read the Acrobat documents on it and read the articles on this site:
Thank you, and John Deubert's book is quite good as well. While the Acrobat UI has changed since the book was written, all the scripting is still the same.