使用自定义按钮将价格变量传递给 PayPal

I have a form and a custom PayPal button, but how do I pass the value/price variable to PayPal?

<form action="https://www.paypal.com/cgi-bin/webscr" method="post">
    <input type="hidden" name="cmd" value="_s-xclick">
    <input type="hidden" name="hosted_button_id" value="ZEFZFYBY2SZB8">
    <input type="image" src="https://www.paypal.com/en_US/i/btn/btn_paynowCC_LG.gif" border="0" name="submit" alt="PayPal - The safer, easier way to pay online!">
    <img alt="" border="0" src="https://www.paypal.com/en_US/i/scr/pixel.gif" width="1" height="1">
</form>

我有一个变量 $total = "238.00";

推荐答案

为金额添加一个隐藏字段

<input type="hidden" name="amount" value="<?php echo $total; ?>">