the checkout form posts to the confirm page.
When adding form elements to the checkout form there are 3 steps you must follow:
1) Add the form element to the checkout page:
<input name="newElement" id="newElement" type="text" />
2) Add a hidden form element on he confirm page with the same name, set to capture the value from the checkout page:
<input name="newElement" id="newElement" type="hidden" value="<?php echo((isset($_POST["newElement"]))?$_POST["newElement"]:"") ?>" />
3) Add the set session value behavior tpo the confirm page to capture the value posted from the checkout page:
<?php
if (!session_id()) session_start();
if($_SERVER["REQUEST_METHOD"] == "POST") {
$_SESSION["newElement"] = "".((isset($_POST["newElement"]))?stripslashes($_POST["newElement"]):"") ."";
}
?>