demo2.html

<div class="mainbody">
    <div class="demo_title">演示代码</div>

    <div class="blank"></div>
    <p id="m-radio">
        <input  type="radio" name="money"  value="10" checked > 0.1元
        <input  type="radio" name="money"  value="500" > 5元
        <input  type="radio" name="money"  value="1000" > 10元
        <input  type="radio" name="money"  value="5000" > 50元
    </p>

    <p id="p-radio">
        <input  type="radio" name="pay"  value="wxpay" checked > 微信支付
        <input  type="radio" name="pay"  value="alipay" > 支付宝
        <input  type="radio" name="pay"  value="jdpay" > 京东钱包
        <input  type="radio" name="pay"  value="qpay" > QQ钱包
    </p>

    <!-- 支付代码接入 开始 -->
    <script
            src="https://payjs.cn/pay.js"
            mch="Wr6BrP"
            amount="10"
            id="popfeng">
        </script>
    <!-- 支付代码接入 结束 -->

</div>

<script src="//cdn.bootcss.com/jquery/3.2.1/jquery.min.js"></script>
<script>
    $(function(){
        $("#p-radio :radio").click(function(){
            var value = $(this).val();
            $("#popfeng").attr("pay",value);
        });

        $("#m-radio :radio").click(function(){
            var value = $(this).val();
            $("#popfeng").attr("amount",value);
        });
    });
</script>