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Re: [VE][html5] http="X-UA-COMPATIBLE" should be valid

From: Jukka K. Korpela <jkorpela@cs.tut.fi>
Date: Thu, 4 Aug 2011 09:01:12 +0300
Message-ID: <F55609EB616B411FBF3CC1DC1F76E973@Vodka6000>
To: <www-validator@w3.org>
Cc: <jfrench@ixley.com>
Leif H Silli wrote:

> Is X-UA-Compatible meta tags used for any other thing than that
> specific thing? AFAIK, X-UA-Compatible is only used for IE browsers:
> Either to trigger a certain "compatibility mode" within IE's native
> Trident engine. OR to trigger IE to start the ChromeFrame.

It is used to select one of the modes of IE. The details are messy and not 
relevant here, since from the perspective of HTML specifications, the issue 
is realism versus attempt at regulate what may appear in meta tags.

> Why these hoops: X-UA-COMPATIBLE cannot occur inside a coniditional
> comment - it doesn't work then. But if the conditional comment is
> placed before the DOCTYPE, then IE moves it into the head element
> before reparsing it (at least, that is what I think happens). Hence
> it works anyhow.

"Conditional comments" and other tricks*) are pointless here. It is so much 
easier to use the meta tag that does the job, following the vendor's 
description, when you are doing something vendor-specific.

So since this is at most about one error message per document, it is easier 
to just let it appear and ignore it.

*) Other tricks include adding the meta tag via client-side scripting. It 
prevents (at present at least) validators from reporting an error, even 
though it does not remove the error (violation of HTML5 drafts treated as 

Received on Thursday, 4 August 2011 06:01:46 UTC

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