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Re: html validation: exactly what is it good for?

From: David Woolley <david@djwhome.demon.co.uk>
Date: Thu, 6 Jul 2006 22:15:51 +0100 (BST)
Message-Id: <200607062115.k66LFpq02143@djwhome.demon.co.uk>
To: www-html@w3.org

> 
> If i build a website, according to his declaration - let say Strict XHTML,

What you describe is not a web site, in the sense of something that is
appropriate to form part of the World Wide Web; it's only suitable for use in
a closed environment, and even then that doesn't account for possibilities
like:

- the browser is upgraded and loses a quirk that is being relied upon;
- the company hires a disabled employee and the assistive technology 
  cannot cope;
- someone finds reasons for using a tool other than the browser, e.g. see
  below.

> and its answering all the roles of Strict Xhtml, but its not valid cause,
> for example, i haven't used "" to surround values, or i haven't closed

I saw a quite good example of this breaking recently on the support forum
for a .NET component that can, amongst other things, convert relative
images to CID: email attachments.  The customer was using a boiler plate,
invalid HTML, tracker image script and an absolute image reference was
misparsed in such a way that it appeared local, but would have appeared
external, if it had been validly quoted.

Admittedly, the component was clearly using heuristic parsing, as it was
"finding" images in scripts, and the customer, appeared to me, to have
expectations of its script handling which would have violated the Turing
Halting Problem.

> single tags using Slash (< />), but other wise i did everything by the
> scheme.

This will break if the site ever serves it as XHTML.  In any case,
the only semi-valid reason I've ever heard of for serving XHTML syntax
as HTML is that one gets strict balancing of tags.

> 
>  What can be the damage?
> If i open the site and see that it works on my target browsers, why i need

As I said, you should only have specific target browsers if you are
in a closed system where management can dictate the software used.
Although it is all too common on the open internet, it is very bad
practice, there.

> the validation for? what do i benefit from it?
> It says it helps me improve my SEO, but i see all the first results at

That's a very cynical reason.

> Content-Type: text/html; charset=ISO-8859-1

(Unnecessary) syntactically (no title) and semantically (all div)
invalid HTML follows!
Received on Thursday, 6 July 2006 21:20:06 GMT

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