<form name="autosubmit" target="_new" action="https://www.paypal.com/cgi-bin/webscr" method="post"><input type="hidden" name="cmd" value="_xclick"><input type="hidden" name="business" value="paypal@your+domain.com">
<input type="hidden" name="item_name" value="%webid%">
<input type="hidden" name="currency_code" value="EUR">
<input type="hidden" name="amount" value="%total%">
<input type="hidden" name="invoice" value="%webid%">
<input type="image" src="http://www.paypal.com/en_US/i/btn/x-click-but01.gif" name="submit" alt="PayPal">
</form>