[[Class]] and host objects

Allen Wirfs-Brock Allen.Wirfs-Brock at microsoft.com
Wed Feb 11 16:56:02 PST 2009

You're right. Too many different browsers open at the same time.  It was probably FF and one of the other I looked at and I didn't look at any prototypes.

Regarding, IE I have no issues with IE being initially incompatible with ES3.1 in this regard.  It's a low impact nonconformance and nothing in the ES3.1 specification actually tests [[Class]]=="Object". However, making it clear in ES3.1 that DOM (I really mean host) objects shouldn't claim to be "Object" (unless they really are) will provide an added incentive for IE to eventually conform.


From: Juriy Zaytsev [mailto:kangax at gmail.com]
Sent: Tuesday, February 10, 2009 10:12 PM
To: Allen Wirfs-Brock
Cc: Mark S. Miller; Brendan Eich; Mark Miller; es-discuss
Subject: Re: [[Class]] and host objects

On Feb 10, 2009, at 9:15 PM, Allen Wirfs-Brock wrote:

>Mark Miller: I like your #2 direction a lot. If it were feasible to require that host objects not even use [[Class]] "Object", I'd be in favor. However, I'm guessing that would differ too greatly from current browser behavior to have a chance.

That's what I thought until I probed around a few DOM objects in IE and Firefox and didn't see any [object "Object"]'s.  We probably need the browser experts to tells whether or not it is common practice to use [[Class]]=="Object" for host objects but a casual inspection looked promising.

I actually see IE6 and 7 having "Object" for most of the host methods' [[Class]]'es. I couldn't find any "Object" [[Class]] nether in FF nor in Gecko. Both, Opera (9.61) and Chrome (1.x) return "Object" for `Element.prototype`


Juriy Zaytsev
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