[Zope] Validating page entry help

[Stuart Foster]

I was wondering what the best way to validate a users input on a page. 

Currently I submit a page to an interim page that checks for certain values
using dtml-if's and dtml-unless'. 
If everything is fine I go on to the next page. If something is missing I
need to go back, I haven't figured out how to do this part.  
If I use <META HTTP-EQUIV="refresh" content=5;URL=<dtml-var
"REQUEST['HTTP_REFERER']">> all the input is lost from the form. 

So my questions are:

1. What is the best way to do page validation before it is submited. 
2. If the way I am doing it seems to be an ok way, how do I go BACK with out
losing everything (equivalent of pressing the back button)

Stuart Foster
MediServe Information Systems

> http://www.mediserve.com
>