ecmascript 5 and the script tag

Allen Wirfs-Brock Allen.Wirfs-Brock at
Fri Apr 17 17:47:13 PDT 2009

>-----Original Message-----
>From: Brendan Eich [mailto:brendan at]
>> IE8 does have a form of global object versioning.  In IE8 the JSON
>> object and associated toJSON methods,  the methods
>> Object.defineProperty and Object.getOwnPropertyDescriptor(they only
>> supports DOM objects in IE8), and a few other minor standards/interp
>> conformance fixes are only provided for pages/iframes operating in
>> "IE8 standards mode" (the default mode).  This was a very late
>> change in the IE development cycle a was primarily made in response
>> to user feedback concerning the IE8 release candidate
>>  ). We'll see how it works out...
>Sorry, I think you mentioned this and I forgot. But this is an all-or-
>nothing mode, I take it -- not a subjective-programming (ES4
>namespaces) facility where one script might run in IE7 mode and see no
>JSON property on the very same global object on which another script
>in IE8 mode sees the ES5 JSON object. Or so I hope!
That's right, it's an all-or-nothing configuration of the global object and the other built-in objects accessed via it.  I would think that a similar interpretation might reasonably be applied to a version specified in the "Content-Script-Type" meta tag.


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