原型中的属性 [英] Property in prototype

问题描述

我想确定一个属性是否在Event原型中可用。

我试过这样做：


if（Event.prototype.srcElement）


但是我得到了一个对WrappedNative原型对象的非法操作

异常。无论如何都要看它是否已经定义。


我还有一个问题是__defineGetter__方法是否是

的一部分Javascript / ECMA脚本版本或者它是Mozilla专有的。


谢谢！

Robert

解决方案

< blockquote>


Robert写道：

另外一个问题是__defineGetter__方法是否是某些Javascript / ECMA的一部分脚本版本或者它是Mozilla专有的。

实现了JavaScript 1.5。该引擎用于Mozilla。所以人们可以说b_b $ b表示__defineGetter__是JavaScript 1.5的一部分，取决于考虑定义该版本的是什么
。

__defineGetter__不属于任何现有的ECMAScript规范

版本。


-


Martin Honnen
http://JavaScript.FAQTs.com/

< blockquote>


Robert写道：

我想确定一个属性是否在Event原型中可用。 />我试过这样做：

if（Event.prototype.srcElement）

但是我得到了一个对WrappedNative原型对象的非法操作
异常。无论如何都要看它是否已经定义。

是Firefox 1.03吗？然后你可能遇到了一个混乱的bug，这里描述了一个

的解决方法：


< http://developer-test.mozilla.org/ en / docs / Working_around_the_Firefox_1.0.3_DHTML_regression>


-


Martin Honnen
http://JavaScript.FAQTs.com/

Martin Honnen写道：

Robert写道：

我想确定一个事件中是否有可用的物业
prototype。
我试过这样做：

if（Event.prototype.srcElement）

但是我在WrappedNative原型上得到了一个非法操作对象
例外。无论如何都要看它是否已经定义。

是Firefox 1.03吗？然后你可能遇到了一个混乱的bug，这里描述了一个解决方法：

不使用Firefox 1.04

Are你暗示Event.prototype.srcElement应该有用吗？

Hi,

I would like to determine if a property is available in an Event prototype.
I tried doing this using:

if (Event.prototype.srcElement)

but I got an "Illegal operation on WrappedNative prototype object"
exception. Is there anyway to see if it already has been defined.

One other question I have is if the __defineGetter__ method is part of
some Javascript/ECMA Script version or if it is Mozilla proprietary.

Thanks!
Robert

解决方案

Robert wrote:

One other question I have is if the __defineGetter__ method is part of
some Javascript/ECMA Script version or if it is Mozilla proprietary.

__defineGetter__ is implemented in the Spidermonkey engine that
implements JavaScript 1.5. That engine is used in Mozilla. So one could
say that __defineGetter__ is part of JavaScript 1.5 depending of what is
considered to define that version.
__defineGetter__ is not part of any existing ECMAScript specification
version.

--

Martin Honnen
http://JavaScript.FAQTs.com/

Robert wrote:

I would like to determine if a property is available in an Event prototype.
I tried doing this using:

if (Event.prototype.srcElement)

but I got an "Illegal operation on WrappedNative prototype object"
exception. Is there anyway to see if it already has been defined.

Is that Firefox 1.03? Then you are probably running into a messy bug, a
workaround is described here:

<http://developer-test.mozilla.org/en/docs/Working_around_the_Firefox_1.0.3_DHTML_regression>

--

Martin Honnen
http://JavaScript.FAQTs.com/

Martin Honnen wrote:

Robert wrote:

I would like to determine if a property is available in an Event
prototype.
I tried doing this using:

if (Event.prototype.srcElement)

but I got an "Illegal operation on WrappedNative prototype object"
exception. Is there anyway to see if it already has been defined.

Is that Firefox 1.03? Then you are probably running into a messy bug, a
workaround is described here:

No I use Firefox 1.04
Are you implying that Event.prototype.srcElement should work?

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