I needed a form for students enrolling in training courses. I couldn't find exactly what I needed out there, so I built my own (borrowing some code from others (credits given in code)). The really important thing was that if, after changing the data, the applicant altered the number of students or hit the back button from the next page, the existing data would not be lost.

Feel free to do whatever with this code, no credit to me required. If you make it better, though, please feel free to e-mail me! Create a form that dynamically changes the number of fields available based on a select list value.