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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
getandsetoperators now allows the identifier to be numeric or a string. bug 520696Function.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 itsjoin()method if one is available or by calling itstoString()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: TheDateobject's parse() method now supports simple ISO 8601 format date strings. - Global objects made read only: The
NaN,Infinity, andundefinedglobal objects have been made read only, per the ECMAScript 5 specification. obj.__parent__andobj.__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().