我正在尝试创建一个贝宝表单，它将 2 个金额框加在一起，如果在特定日期购买，总金额减去 5 美元。几天来我一直在尝试这样做，但一无所获。以下是我拥有的代码；感谢所有帮助:)
<form action="https://www.paypal.com/cgi-bin/webscr" method="post">
<input type="hidden" name="cmd" value="_xclick">
<input type="hidden" name="business" value="ZNRGUCQ5GN4HU">
<input type="hidden" name="lc" value="US">
<input type="hidden" name="item_name" value="Gaslight Registration">
<input type="hidden" name="amount" value="40.00">
<input type="hidden" name="currency_code" value="USD">
<input type="hidden" name="button_subtype" value="services">
<input type="hidden" name="no_note" value="0">
<input type="hidden" name="cn" value="Is your Angel donation assigned? to who?">
<input type="hidden" name="no_shipping" value="1">
<input type="hidden" name="rm" value="1">
<input type="hidden" name="return" value="http://gaslight.endogaming.net">
<input type="hidden" name="cancel_return" value="http://gaslight.endogaming.net">
<input type="hidden" name="bn" value="PP-BuyNowBF:btn_paynow_LG.gif:NonHosted">
<table>
<tr><td><input type="hidden" name="on0" value="Character Name">Character Name</td></tr><tr><td><input type="text" name="on0" maxlength="200"></td></tr>
<tr><td>Angel Donation</td></tr><tr><td><input type="text" name="amount" maxlength="60"></td></tr>
</table>
<input type="image" src="https://www.paypalobjects.com/en_US/i/btn/btn_paynow_LG.gif" border="0" name="submit" alt="PayPal - The safer, easier way to pay online!">
<img alt="" border="0" src="https://www.paypalobjects.com/en_US/i/scr/pixel.gif" width="1" height="1">
</form>