为脚本标记自定义自己的 src 时未定义 Paypal

问题描述

在我的项目中，我使用 PayPal 实现 (https://developer.paypal.com/docs/checkout?keywords=checkout) 使付款成为可能。

首先，我询问客户他喜欢哪种付款方式，并在此基础上生成相应的付款按钮（paypal、信用卡或bancontact）。当我使用下面的代码时，出现以下错误：

未捕获的引用错误：paypal 未定义。

如下所示，我在触发 PayPal 代码之前将正确的脚本标记添加到我的 HTML 代码中，所以这应该不是问题。

HTML 代码 (paypal-div)

<div id="paypal-button-container"></div>

JavaScript 代码

let radios = document.querySelectorAll('.pm');
const script = document.createElement("script");
let src = '';

radios.forEach(radio => {
    if (radio.checked) {
        supper_data.payment_method = (radio.value).charAt(0).toUpperCase() + (radio.value).slice(1);   

        if((radio.value).charAt(0).toUpperCase() + (radio.value).slice(1) === "Bancontact") { 
            src = 'https://www.paypal.com/sdk/js?client-id=ASuRqSAZYj9/*...*/-FEXCHWao5SA7-SADYX6werETXouaJDIBP1UeSAJpJbMbrtCOy59C7C-C&currency=EUR&disable-funding=card,sofort,credit';
        } else if (supper_data.payment_method === "Visa") {
            src = 'https://www.paypal.com/sdk/js?client-id=ASuRqSAZYj9/*...*/-FEXCHWao5SA7-SADYX6werETXouaJDIBP1UeSAJpJbMbrtCOy59C7C-C&currency=EUR&disable-funding=bancontact,credit';
        } else {
            src = 'https://www.paypal.com/sdk/js?client-id=ASuRqSAZYj9/*...*/-FEXCHWao5SA7-SADYX6werETXouaJDIBP1UeSAJpJbMbrtCOy59C7C-C&currency=EUR&disable-funding=bancontact,card';
        }

    }
});

script.type = "text/javascript";
script.src = src;
document.head.append(script);

document.querySelector('#paypal-button-container').style.display = "block";

paypal.Buttons({
    style: {
        shape: 'pill',color: 'blue'
    },createOrder: (data,actions) => {
        return actions.order.create({
            purchase_units: [{
                amount: {
                    currency_code: "EUR",value: price
                }
            }]
        });
    },onApprove: (data,actions) => {
        return actions.order.capture().then((details) => {
            $.ajax({
                url: "./includes/delete-cart.php",method: "GET",success: function (data) {
                    Swal.fire({
                        icon: 'success',title: 'Betaling Afgerond',text: 'Uw bestelling is ontvangen.'
                    }).then(() => {
                        window.location.reload();
                    })
                    console.log(details);
                }
            });
        })
    }
}).render('#paypal-button-container');

解决方法

以这种方式加载脚本是异步的并且需要时间，因此您应该使用 onload 事件回调

//Helper function

function loadAsync(url,callback) {
  var s = document.createElement('script');
  s.setAttribute('src',url); s.onload = callback;
  document.head.insertBefore(s,document.head.firstElementChild);
}

// Usage -- callback is inlined here,but could be a named function

loadAsync('https://www.paypal.com/sdk/js?client-id=sb&currency=USD',function() {
  paypal.Buttons({

    // Set up the transaction
    createOrder: function(data,actions) {
        return actions.order.create({
            purchase_units: [{
                amount: {
                    value: '0.01'
                }
            }]
        });
    },// Finalize the transaction
    onApprove: function(data,actions) {
        return actions.order.capture().then(function(details) {
           //...
        });
    }

  }).render('#paypal-button-container');
});