That looks like what I needed to know, but...
I'm using a template system and I'm calling my pages like this:
If a user inputs something wrong on the index.php?page=checkout form,
it goes to index.php?page=confirm where it fails validation.
It should send the user back to index.php?page=checkout to correct the fields, but it sends the user back to index.php?page=Checkout&page=Confirm
This sends the user on to the confirm page which is wrong.
How do I keep it from adding &page=confirm to the query string?