<script src="jquery-3.4.1.min.js"></script>
    <script src="qrcode.min.js"></script>
<script>
 $.ajax({
        type: 'get',
        url: url,
        dataType: "json",
        success: function (res) {
            layer.close(loading);
            var no = res.no;
            new QRCode(document.getElementById("wx_ewm"),{//对象
                text: decodeURIComponent(res.url),//解码微信支付二维码
                width: 120,//二维码大小
                height: 120,//二维码高
                colorDark : "#000000",
                colorLight : "#ffffff",
                correctLevel : QRCode.CorrectLevel.H//级别
            } );
            var url = "";//回调url
            var data = {'no': no};//订单号
            clearInterval(timer);
            timer = setInterval(function(){
                $.post(url,data,function(res){
                    if(res == 'yes'){
                        parent.location.href = "";//支付成功跳转地址
                    }
                })
            },3000)
        },
        error: function (res) {
            console.log(res)
        }
    });

</script>