不多说，上完整代码！

<!DOCTYPE html>
<html lang="zh-CN">
<head>
    //这里是应有的css文件引用
    <?php require "app/admin/view/layout/header.html" ?>
</head>
<body>
<div class="layui-card-body text-center" style="box-sizing: border-box;">
    <div id="qrcode" class="layui-inline"></div>
    <h2 style="color: red;padding-top:20px">请使用微信扫码支付</h2>
</div>
 //这里是应有的js文件引用
<?php require "app/admin/view/layout/footer.html" ?>

<script>

    layui.use(['form', 'QRCode'], function () {
        var $ = layui.jquery;
        var form = layui.form;
        var QRCode = layui.QRCode;

        new QRCode(document.getElementById("qrcode"), {
            text: '二维码的短地址',
            width: 250,
            height: 250,
            colorDark: '#000000',
            colorLight: '#ffffff',
            correctLevel: QRCode.CorrectLevel.H,
        });


        //1.支付轮询
        $(document).ready(function () {
            setInterval(function () {
                //1.先得到当前iframe层的索引 关闭窗口
                var index = parent.layer.getFrameIndex(window.name);
                $.post("后台url",
                    {out_trade_no: "订单号"},
                    function (res) {
                    if (res.code === 200) {
                        layer.msg(res.msg, {icon: 1, time: 2500, shade: 0.4}, function () {
                            parent.layer.close(index); //2.再执行关闭自身
                            parent.location.reload();
                        });
                    }
                }, 'json');
                return false;
            }, 3000);
        });
    });
</script>
</body>
</html>