Yes, progress. The calculator on the cart page now works. Some customers don't bother with the calculator, so the postal code entered on the checkout page has to be used to automatically add tax.
On the checkout page, only entering the first letter or checking the tax exempt will provide results, the complete postal code throws the error messages.
Just to be sure, I added the code to the checkout page and then also to the confirm page. But no luck.
<?php
if (!session_id()) session_start();
if($_SERVER["REQUEST_METHOD"] == "POST") {
$_SESSION['userpostcode'] = (isset($_POST["postcode"]))?substr($_POST["postcode"],0,1):"";
}
?>
