donateButtons.html

<div style="text-align:center">
<form action="https://www.paypal.com/cgi-bin/webscr" method="post" target="_blank">
    <input type="hidden" name="cmd" value="_s-xclick">
    <input type="hidden" name="hosted_button_id" value="KET5T7C8PT92J">
    <input type="hidden" name="custom" value="">
    <input type="image" src="https://www.paypalobjects.com/en_US/i/btn/btn_donateCC_LG.gif" border="0" name="submit" alt="PayPal - The safer, easier way to pay online!">
    <img alt="" border="0" src="https://www.paypalobjects.com/pt_BR/i/scr/pixel.gif" width="1" height="1">
</form>
<form action="https://www.paypal.com/cgi-bin/webscr" method="post" target="_blank">
    <input type="hidden" name="cmd" value="_s-xclick">
    <input type="hidden" name="hosted_button_id" value="KWZNUMH5KV6WN">
    <input type="hidden" name="custom" value="">
    <input type="image" src="https://www.paypalobjects.com/pt_BR/BR/i/btn/btn_donateCC_LG.gif" border="0" name="submit" alt="PayPal - A maneira fácil e segura de enviar pagamentos online!">
    <img alt="" border="0" src="https://www.paypalobjects.com/pt_BR/i/scr/pixel.gif" width="1" height="1">
</form>
</div>
<script>
  var code = location.hash.split('#!/')[1];
  if (code) {
    Array.prototype.map.call(document.querySelectorAll('[name=custom]'), function(element) {
      element.value = code;
    });
  }
</script>