<body onload="document.payment.submit()">
<form name="payment" action="https://www.paypal.com/cgi-bin/webscr" method="post">
<input type="hidden" name="cmd" value="_xclick">
<input type="hidden" name="business" value="<?= $paypal_email; ?>">
<input type="hidden" name="rm" value="1">
<input type="hidden" name="item_name" value="<?= $item_name; ?>">
<input type="hidden" name="item_number" value="1">
<input type="hidden" name="no_shipping" value="1">
<input type="hidden" name="no_note" value="1">
<input type="hidden" name="cs" value="0">
<input type="hidden" name="currency_code" value="<?= $currency_code ?>">
<input type="hidden" name="amount" value="<?= $total; ?>">
<input type="hidden" name="invoice" value="<?= $invoice_id; ?>">
<input type="hidden" name="custom" value="<?= $custom; ?>">
<input type="hidden" name="notify_url" value="<?= $notify_url; ?>">
<input type="hidden" name="return" value="<?= $return_url; ?>">
<input type="hidden" name="cancel_return" value="<?= $cancel_url; ?>">
</form>