Sorry for this.
Here is the form in html that I use:
<form action='https://www.sandbox.paypal.com/cgi-bin/webscr' method ='POST' id='paypal' onsubmit='return true' name='Form' >
<?php
$graphic = $_POST["Graphic"];
$Price = $_POST["Price"];
$Person = $_POST["Person"];
?>
<input type='hidden' name='cmd' value='_cart' >
<input type='hidden' name='business' value='xxxxxxx' >
<input type='hidden' name='upload' value='1' >
<INPUT TYPE='hidden' id='RETURL' NAME='return' >
<script>
URL = 'https://ecovib2d.com.au/workfromhome/yourart/';
Person = <?php echo json_encode($Person); ?>;
Graphic = <?php echo json_encode($graphic); ?>;
document.getElementById('RETURL').value = URL + Person + '/Graphic/' + Graphic ;
</script>
<INPUT TYPE='hidden' NAME='currency_code' value='AUD'>
<input type='hidden' id='Item1' name='item_name_1' >
<script>
document.getElementById('Item1').value = 'Your Graphic in JPEG format -' + Graphic ;
</script>
<input type='hidden' id='Cost' name='amount_1' >
<script>
Price = <?php echo json_encode($Price); ?>;
document.getElementById('Cost').value = Price;
</script>
<INPUT TYPE='hidden' name='address_override' value='1' >
</form>
