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Re: Content negotiation

From: Nir Dagan <nir@nirdagan.com>
Date: Wed, 27 Jan 1999 03:00:43 GMT
Message-Id: <199901261748.SAA15468@sahara.upf.es>
To: w3c-wai-gl@w3.org
Content negotiation and the type attribute 
are distinct topics.

I would say:
1. Serve your documents with the correct Content-Type HTTP header. 
Include a charset parameter whenever might be ambiguity the encoding.
[Priority 1]

2. When refrering from an HTML document to a document with 
a MIME type which is not natively undertood to many user agents, 
specify the type attribute.
[Priority 3]

The rationale for this is that this may save the user agent 
work, and reduce internet traffic (I am not sure that this has 
to do with accessibility). E.g., if the type of an OBJECT is 
not supported by a browser it can avoid making an HTTP 
request for it. Or save indexing robots retrieving documents 
that they can't analize.

Content negotiation.
3. If a resource is served in various formats or languages
use content negotiation to determine the format/language 
preferred to the user. [priority 3]
Also provide a "manual option" (e.g., a link) to switch from 
one version to another. [priority 1]

The last one is not only for backward compatibility. Sometimes 
a user may like to check out more than one format. 
(e.g., HTMl to read online, and then if I like it PDF to 
make a printed version)

Nir Dagan
Assistant Professor of Economics
Universidad Pompeu Fabra
Ramon Trias Fargas 25
08005 Barcelona


"There is nothing quite so practical as a good theory." 
-- A. Einstein
Received on Tuesday, 26 January 1999 12:58:44 UTC

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