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Re: Image width specification in html5

From: Arthur Clifford <art@artspad.net>
Date: Mon, 21 Nov 2011 00:16:43 -0800
Message-Id: <B16537F2-0ECC-479E-9750-E4E671C5B589@artspad.net>
To: public-html-comments@w3.org
Anybody know why that particular decision was made? Given how long that has been an industry standard it seems a weird thing to ditch.

Art C

On Nov 21, 2011, at 12:10 AM, Michael[tm] Smith wrote:

> David Swindlehurst <davidms@uwclub.net>, 2011-11-20 13:55 +0000:
> 
>> <div class="?"><img src="image.png" alt="ancient grey-haired awkward person"
>> width="25%" /></div>
>> 
>> results in an error - the Validator expects an absolute number (of pixels!).
>> Fixing image width like this prevents correct rendering of the page in any
>> size of display different from the writer's original. Although there is a
>> mass of insignificant discussion in the current Specification about the
>> "alt" tag, there is no mention of image sizing at all, which seems to me to
>> be far more important. Does the Spec need revising, or is the Validator
>> wrong in expecting an absolute number?
> 
> The relevant part of the spec is this:
> 
>  http://dev.w3.org/html5/spec/the-map-element.html#attr-dim-width
>  Author requirements: The width and height attributes on img, iframe,
>  embed, object, video, and, when their type attribute is in the Image
>  Button state, input elements may be specified to give the dimensions of
>  the visual content of the element (the width and height respectively,
>  relative to the nominal direction of the output medium), in CSS pixels.
>  The attributes, if specified, must have values that are valid
>  non-negative integers.
> 
> "25%" is not an integer, so the validator behavior conforms to the spec in
> correctly reporting an error for it.
> 
> See also the last part of the "Changed Attributes" section of the "HTML5
> differences from HTML4" document, which says:
> 
>  "The width and height attributes on img and other elements are no longer
>  allowed to contain percentages."
> 
>  --Mike
> 
> -- 
> Michael[tm] Smith
> http://people.w3.org/mike/+
> 
Received on Monday, 21 November 2011 08:17:09 GMT

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