Internet Explorer 8 不支持 JavaScript object 和属性

Question

我创建了一个具有一些属性的 JavaScript object 并将一些值放入其中：

var summaryViewObject[transactionId] = new Object();
summaryViewObject[transactionId].paymentTotal = 0;
summaryViewObject[transactionId].numberOfTransactions = 0;
summaryViewObject[transactionId].returnedPayment = false;

当我们得到像returnedPayment等属性时，它在 IE8 中显示错误，但在 Chrome、IE9 和 Firefox 等其他浏览器中工作正常。

请帮助我了解 JavaScript object 和属性支持。

错误类型错误：无法获取属性“returnedPayment”的值：object 是 null 或未定义

Answer 1

这一行：

var summaryViewObject[transactionId] = new Object();

无效，因为summaryViewObject未定义，您无法在定义它之前在其上创建[transactionId]属性。

尝试这个：

var summaryViewObject = {};
summaryViewObject[transactionId] = {};
summaryViewObject[transactionId].paymentTotal = 0;
summaryViewObject[transactionId].numberOfTransactions = 0;
summaryViewObject[transactionId].returnedPayment = false;

此外， = new Object()和= {}; 本质上是一样的。

Answer 2

这应该有效：

var transactionId = 0;
var summaryViewObject = new Array();
summaryViewObject[transactionId] = ({
    paymentTotal: 0,
    numberOfTransactions: 0,
    returnedPayment: true});

//These lines below are here to show you that you can now edit them like so:
summaryViewObject[transactionId].paymentTotal = 0;
summaryViewObject[transactionId].numberOfTransactions = 0;
summaryViewObject[transactionId].returnedPayment = false;

//should alert "false" even though we set it to true in the declaration
alert(summaryViewObject[transactionId].returnedPayment);