W3C home > Mailing lists > Public > public-html@w3.org > November 2007

Re: Format for type attribute value

From: Julian Reschke <julian.reschke@gmx.de>
Date: Tue, 20 Nov 2007 08:32:26 +0100
Message-ID: <47428D8A.3000103@gmx.de>
To: Boris Zbarsky <bzbarsky@MIT.EDU>
CC: "public-html@w3.org List" <public-html@w3.org>

Boris Zbarsky wrote:
> 
> Julian Reschke wrote:
>> Multiple media-type values? What would that be good for?
> 
> Rendering the web?  In particular, it's not uncommon for servers (esp. 
> when CGIs are involved) to produce things like:

Boris, when I wrote this I thought somebody found a *spec* allowing 
this, which would be completely pointless.

>   Content-Type: text/html; charset=ISO-8859-1
>   Content-Type: text/plain
> 
> which then get normalized to:
> 
>   Content-Type: text/html; charset=ISO-8859-1, text/plain

That's a bit misleading; and the incorrect BNF fragment in 
<http://mxr.mozilla.org/firefox/source/netwerk/base/src/nsURLHelper.cpp#842> 
isn't helpful either (because it claims that this is what RFC2616 says).

Having multiple Content-Type headers makes the HTTP message invalid 
(<http://tools.ietf.org/html/rfc2616#section-4.2>). And yes, I 
understand the choices for the UA at this point aren't pretty:

1) report an error and abort
2) ignore the Content-Type headers
3) pick one of them (how)
4) ...more?

It would be interesting to know when this happens (is there a FF 
extension that can report that error?).

> Not sure where that normalization happens offhand (server end or Gecko 
> end).

It really doesn't matter; both variations are illegal.

Best regards, Julian
Received on Tuesday, 20 November 2007 07:59:27 UTC

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