New in JavaScript 1.8.5

以下為 JavaScript 1.8.5 的更新日誌，此版本被涵蓋於 Firefox 4 之中。

JavaScript 1.8.5 新功能

新函數

函數	敘述
`Object.create()`	基於一個特定的原型物件和屬性，建立一個新物件。bug 492840
`Object.defineProperty()`	Adds the named property described by a given descriptor to an object.
`Object.defineProperties()`	Adds the named properties described by the given descriptors to an object.
`Object.getOwnPropertyDescriptor()`	Returns a property descriptor for a named property on an object. bug 505587
`Object.keys()`	Returns an array of all enumerable properties on an object. bug 307791
`Object.getOwnPropertyNames()`	Returns an array of all enumerable and non-enumerable properties on an object. bug 518663
`Object.preventExtensions()`	Prevents any extensions of an object. bug 492849
`Object.isExtensible()`	Determine if extending of an object is allowed. bug 492849
`Object.seal()`	避免其他程式碼刪除一個物件的屬性。 bug 492845
`Object.isSealed()`	Determine if an object is sealed. bug 492845
`Object.freeze()`	凍結一個物件：其他程式碼無法刪除或更便任何屬性。bug 492844
`Object.isFrozen()`	辨識一個物件是否遭凍結。bug 492844
`Array.isArray()`	檢查一個變數是否為陣列。bug 510537
`Date.prototype.toJSON()`	回傳一個 JSON 格式的字串給`Date` 物件。
`Function.prototype.bind()`	Creates a new function that, when called, itself calls this function in the context provided (with a given sequence of arguments) bug 429507

New ECMAScript5 features

get and set operators now allows the identifier to be numeric or a string. bug 520696
Function.apply() can accept any array-like object as the arguments list, instead of only true arrays.
strict mode support
Array.toString() now works even on non-arrays by either returning the result of calling its join() method if one is available or by calling its toString() method.

Other standardization work

Various non-standard syntaxes for defining getters and setters have been removed; ECMAScript 5 defined syntax has not been changed. These were all pretty esoteric and rarely used; if this affects you, see this blog post for details.

新物件

Object	Description
`Proxy`	Offers support for creating `Object` and `Function` proxies that enable meta-programming in JavaScript.

Changed functionality in JavaScript 1.8.5

ISO 8601 support in Date: The Date object's parse() method now supports simple ISO 8601 format date strings.
Global objects made read only: The NaN, Infinity, and undefined global objects have been made read only, per the ECMAScript 5 specification.
obj.__parent__ and obj.__count__ become obsolete. Some information about why: SpiderMonkey change du jour: the special __parent__ property has been removed bug 551529 & bug 552560.
Trailing commas no longer accepted in JSON.parse().

最近修改: Mar 23, 2019, 由 MDN 貢獻者