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

Re: Let every element have a src attribute

From: Dao Gottwald <dao@design-noir.de>
Date: Tue, 03 Apr 2007 10:12:38 +0200
Message-ID: <46120C76.8090409@design-noir.de>
To: Matthew Raymond <mattraymond@earthlink.net>
CC: public-html@w3.org

Matthew Raymond wrote:
 > Dao Gottwald wrote:
 >> Matthew Raymond wrote:
 >>> Dao Gottwald wrote:
 >>>> Elliott Sprehn wrote:
 >>>>> This would seem to complicate semantics to me. What's the difference
 >>>>> between <p src=""> and <div src=""> in terms of the meaning of the
 >>>>> replaced content?
 >>>> The first replaces a paragraph by an external source, the latter
 >>>> replaces, well ... anything (since div doesn't carry significant 
semantics.)
 >>>    That's interesting, because I thought it was the other way around.
 >>> The content is supposed to replace the image if the image doesn't load.
 >>  From the XHTML2 WD:
 >>
 >> (1) "This collection causes the contents of a remote resource to be
 >> embedded in the document in place of the element's content."
 >> (2) "If accessing the remote resource fails, [...] the content of the
 >> element must be processed instead."
 >>
 >> Both aspects are perfectly consistent.
 >
 >    That's not consistent with HTML, though. The above makes this...
 >
 > | <p src="image.png">[...]</p>
 >
 >    ...the equivalent to this...
 >
 > | <p><img src="image.png" alt="[...]"></p>
 >
 >    However, consider an image in the middle of a sentence:
 >
 > | <p>This sentence has <img src="image.png" alt="[...]"> in it.</p>
 >
 >    Using a global |src| attribute, you're actually forced to insert
 > markup simply to use the attribute:
 >
 > | <p>This sentence has <span src="image.png">[...]</span> in it.</p>

Could you elaborate on the problem that you see here? If you don't want 
to replace the whole paragraph, it makes perfectly sense not to use 
<p>'s src attribute.

 >    What's more is that in XHTML, there's no reason people couldn't do
 > the following:
 >
 > | <p>This sentence has <img src="image.png">[...]</img> in it.</p>
 >
 >    That's actually shorter than using <span> for the same thing, while
 > not forcing you to leave a container element when the image fails to 
load.

As I said, it's not backwards-compatible.

 >> Apparently we're talking about different types of images. I'm not
 >> proposing to remove <img>, [because] there are clearly images that 
aren't
 >> just text replacements / can't be replaced by text.
 >
 >    In my opinion, that represents the only truly semantic use case.

In my opinion, it doesn't.

 >> Yet there are images
 >> that do communicate well-definable chunks of information.
 >>
 >> An example: http://design-noir.de/log/2006/12/immer-noch-nicht-gezahlt/
 >
 >    The image is irreplaceable when you're using it as evidence, so while
 > text fallback for the letter is enough to read the letter, it is simply
 > a distant second best to the image itself.

The image could be replaced very well by multiple paragraphs and 
emphasises. That you consider a big text string as "enough" is probably 
due to the fact that you're not disabled.

 >> Or just think of the million logos out there, like
 >> <http://www.linguatec.net/images/logos/linguatec.de.gif>.
 >
 >    The whole point of a logo is to leave a visual imprint in the
 > viewer's mind, so once again, the image is more important than the text
 > that might replace it if it fails to load.

... which was not my point. My point was and is that the image's 
information can and should be available as markup.

 >>>    Then why not just use <object>?
 >> Its fallback mechanism isn't well supported,
 >
 >    This makes no sense. A global |src| attribute isn't supported at all
 > in HTML, and I doubt that it would be any easier for browser vendors to
 > implement given their track record with <object>.

The proposed fallback-mechanism is supported out of the box.
Technically, Opera already supports replacing an element's contents via 
CSS3 (content: url(...)).

 >> and I'd like to avoid the more complex markup.
 >
 >    What complex markup? Right now, the following is perfectly valid:
 >
 > | <object data="image.png"> [...Fallback...] </object>
 >
 >    How is that any more complicated than the following?
 >
 > | <p src="image.png> [...Fallback...] </p>

Actually:

<object data="image.png"> <p> [...Fallback...] </p> </object>
vs.
<p src="image.png> [...Fallback...] </p>

That should be more obvious.

 >    Sure, it's a few more characters to type, but one thing it's good for
 > is allowing better fallback:
 >
 > | <object data="...">
 > |   <object data="...">
 > |     <object data="...">
 > |       [...Fallback...]
 > |     </object>
 > |   </object>
 > | </object>
 >
 >   ...Versus...
 >
 > | <p src="">
 > |   <p src="">
 > |     <p src="">
 > |       [...Fallback...]
 > |     </p>
 > |   </p>
 > | </p>
 >
 >    Not the in the above for <object>, just the fallback line is used if
 > the objects fail to load. However, if the objects pointed to by |src|
 > fail to load, you get this:
 >
 > | <p><p><p>[...Fallback...]</p></p></p>

Nesting <p> is neither allowed nor supported in any browser.

 >>>>> Also, what benefit beyond slightly reducing the markup by 
removing the
 >>>>> <object> tag does this provide?
 >>>> It's more intuitive and links the external source with the 
semantics it
 >>>> carries directly.
 >>>    I don't see it as more intuitive at all. What the heck is "src"
 >>> supposed to mean to anyone?
 >> Are you kidding me?
 >
 >    Not at all. Consider the following:
 >
 > | <!-- The |src| attribute provides the URL for the image. -->
 > | <img src="Stargate">
 > |
 > | <!-- The |src| attribute provides the URL for the video. -->
 > | <video src="X-303">
 > |
 > | <!-- The |src| attribute provides the URL for an audio file. -->
 > | <audio src="Zat">
 > |
 > | <!-- The |src| attribute provides the URL for...a paragraph??? -->
 > | <p src="DHD">

Exactly.

 >    Furthermore, |src| is already defined with different semantics on
 > several elements, and for those who are just learning HTML, it doesn't
 > necessarily indicate image or object semantics. In fact, the names
 > "image" or "object" would have been better choices.

In fact, neither XHTML2 nor I did limit the given proposal to images. 
The "remote resource" may very well be any media.

 >>>    The image IS the semantics! If it wasn't, you could just use 
CSS. The
 >>> surrounding markup doesn't define the image any more than the
 >>> surrounding text defines a particular word.
 >> Just as with text, an image isn't self-descriptive, even it it contains
 >> the semantics.
 >
 >    The content we're talking about isn't supposed to describe an image,
 > it's supposed to replace it. There's a difference.

Exactly! And since an image's information can be complex, the alt 
attribute isn't enough to replace it.
But I wasn't actually referring to the replaced content but to the plain 
tag that describes the content as being a paragraph or whatever.
Received on Tuesday, 3 April 2007 08:12:53 UTC

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