W3C home > Mailing lists > Public > www-style@w3.org > July 2004

Re: [CSS21] Error handling of missing style sheets

From: Justin Wood <jw6057@bacon.qcc.mass.edu>
Date: Thu, 15 Jul 2004 01:20:43 -0400
Message-ID: <40F6142B.5010102@bacon.qcc.mass.edu>
To: Mark Moore <mark.moore@notlimited.com>
Cc: www-style@w3.org

Mark Moore wrote:

>According to section 3.2:
>2.	For each source document, it must attempt to retrieve all associated
>style sheets that are appropriate for the supported media types. If it
>cannot retrieve all associated style sheets (for instance, because of
>network errors), it must display the document using those it can retrieve.
>According to section 3.3:
>In general, this document does not specify error handling behavior for user
>agents (e.g., how they behave when they cannot find a resource designated by
>a URI). 
>However, user agents must observe the rules for handling parsing errors. 
>Since user agents may vary in how they handle error conditions, authors and
>users must not rely on specific error recovery behavior.
>I would suggest changing 3.2 to clarify whether partial style sheets (e.g.
>network error occurs during retrieval) should be discarded or used.  I would
>recommend they be discarded.
I disagree, if there is a netword error, I'd rather my stylesheets be at 
the least 'allowed' to be used for what was received, in { ... } breaks 
(inside) the whole { ... } is discarded based on parsing error!  if a UA 
chooses to discard whole sheet, ok.  if it chooses to allow what it 
already received, great.  But I do not feel we should force this on any UA.

>I would suggest two changes to 3.3:
>1) Change the second sentence to mention handling of missing style sheets
>(e.g. " However, user agents must observe the rules for handling parsing
>errors and unretrievable style sheets.")
This would remove the intent of the second sentence and become 
excessively repetative, we "provide no rules for missing style sheets" 
(unrecoverable).  but parsing rules are an entirely different story.

>2) Clarify whether the specified parsing errors, or missing style sheets are
>expected or permitted to raise any exception to the User.

"Expected" -- Never (imo);  and permitted -- Always (since we do not 
force any error handling conditions, if a UA chooses to msg the user in 
some way available to them let them), though imo a UA should not pop-up 
warnings about missing stylesheets, do we pop-up warnings about missing 
background images (IE or Mozilla as my example)?

Thanks for listening
~Justin Wood, (non W3C WG member, stated as such, so my words are not 
interpreted as a claim of  'fact')
Received on Thursday, 15 July 2004 01:22:26 UTC

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