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Re: Dropping <input usemap="">

From: Philip Taylor <philip@zaynar.demon.co.uk>
Date: Wed, 15 Aug 2007 16:14:58 +0100
Message-ID: <46C31872.4020605@zaynar.demon.co.uk>
To: Robert Burns <rob@robburns.com>
CC: public-html <public-html@w3.org>

Robert Burns wrote:
> Thanks for the additional statistics. However, I just don't know what 
> these are supposed to show. No site is going to break because their 
> |blink| element didn't work.

They will still break, though to a much more limited extent, since IE 
users won't get the optimal viewing experience that the author intended 
and may miss out on the intended emphasis of some parts of the page - 
the numbers aren't directly comparable with the numbers for features 
that break to a less limited extent, but they still give some indication 
that many people are happy to use features that are not interoperable 
and are not supported by the majority browser.

> However, creating a client-side image map 
> that submits form data, is not something that can sorta work in some 
> browsers and not in others.

I may be misunderstanding you, but it's never possible to create 
client-side image maps that submit form data in any browser - form 
submission only happens as part of server-side image maps.

When they are mixed, like in 
<http://software.hixie.ch/utilities/js/live-dom-viewer/?%3C%21DOCTYPE%20html%3E%0D%0A%3Cbody%3E%0D%0A%3Cmap%20name%3Dm%3E%3Carea%20shape%3Drect%20coords%3D0%2C0%2C100%2C100%20href%3Dhttp%3A//google.com%3E%3C/map%3E%0D%0A%3Cform%20action%3D.%3E%3Cinput%20type%3Dimage%20src%3Dimage%20usemap%3D%23m%3E%3C/form%3E>
in Firefox and Opera, the left half of the image (under an <area>) is 
just a plain client-side image-map link, and the right half (not under 
any <area>) is a server-side image-map form-submission button.

In IE, the client-side image-map will be ignored and the whole of the 
image will act as the server-side image-map form-submission button. So 
you can still use <input usemap> without breaking in IE, if you make 
your server-side code redirect the user as appropriate. But even though 
you can easily make it work, the collected data suggests that almost 
nobody does that.

> My question would be if <input type='image' usemap=''> is 
> easily dropped in favor of <img usemap=''>, then why isn't <input 
> type='image'> also easily dropped in favor of <img>?

It would have to be in favour of something like <button style="border: 
none; background: transparent"><img ...></button> to get the 
form-submission effect. It wouldn't be able to do the 
form-submission-with-x-and-y-coordinates effect at all. I have no idea 
how much people rely on the latter effect - it would be useful to find 
out how it's used.

> Why aren't we discussing dropping @ismap from |input|?

That attribute has been dropped already - <input type=image> always 
submits the x and y values, regardless of whether you specify ismap. 
(That matches what IE/FF/Opera (and probably Safari) do.)

> what's so important about 
> purging the language. Let's focus on the interoperability, on more 
> consistent parsing and rendering and on the new semantics.
> What's the point of spending all this time trying to purge these pieces.

Interoperability and consistency can be achieved less expensively by 
removing a feature than by specifying it, implementing it, testing it, 
describing it in tutorials and books, etc. <input usemap> would have a 
similar cost to an entirely new feature, since there is no adequate 
specification of its current behaviour (HTML4 says almost nothing, and 
isn't even consistent about whether it's specified or not [1]) and it is 
not yet widely implemented or documented. The cost has to be balanced 
against the benefits, and it looks like people have not seen a 
convincing demonstration that the benefits are sufficient.


[1] http://www.w3.org/TR/html4/appendix/notes.html#h-B.6.2 - "Future 
projects: ... Another possible extension would be to add the usemap 
attribute to INPUT for use as client-side image map when "type=image""

-- 
Philip Taylor
philip@zaynar.demon.co.uk
Received on Wednesday, 15 August 2007 15:15:34 UTC

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