W3C home > Mailing lists > Public > www-style@w3.org > July 2007

Re: unite two space: attributes and properties

From: Martin Atkins <mart@degeneration.co.uk>
Date: Mon, 16 Jul 2007 19:30:47 +0100
Message-ID: <469BB957.8060307@degeneration.co.uk>
Cc: www-style@w3.org

Dmitry Turin wrote:
> Good day, Martin.
>>> p[color="red"] {...}
>>> table          {cellspacing:0}
>>> <span color="red" class="a">
> MA> all presentational attributes in HTML should have equivilant properties in CSS ...
> +1
> MA> ... exact name, content model and usage may differ.
> -1
> I thought exactly about this, when i created topic.
> MA> HTML doesn't have a "color" attribute on SPAN.
> -1 for me.
> I messed two ideas in one letter without comments:
> idea of unification "in vertical"
>  (unification of attribute's and property's names, content model and usage),
> and idea of unification "in horizontal"
>  (unification by extending of presentational features to all tags -
>  as far, as it's possible).

So as far as I can tell, you are proposing that:
  * All CSS properties be allowed as HTML attributes, and
  * All HTML attributes be allowed as CSS properties

This is troublesome for a number of reasons:

  * There are some situations where HTML attributes and CSS properties 
overlap with different parsing rules or semantics. For example, <TABLE 
BACKGROUND="#ffffff"> is not correct: the BACKGROUND attribute expects a 
URI, not a colour. CSS, on the other hand, considers "background" to be 
a shorthand for a number of other properties, including background-image.

  * As hinted on in the previous point, there is a massive overlap 
between CSS properties and HTML attributes. In order to mix the two, 
you'd have to define what happens when a UA encounters (for example) 
<table bgcolor="red" background-color="blue">, or you'd have to throw 
away either most of HTML or most of CSS.

  * CSS is fundamentally about presentation, so there are plenty of HTML 
attributes that really have no place in CSS. For example:
       a#home { href: "/index.html"; }

  * In HTML, attribute value types are generally determined by 
convention or specification, while CSS determines these by syntax. See 
my above example where the HTML HREF attribute expects a string 
containing a URI while CSS would normally use url("/index.html").

I think really your main qualm is that the style="" attribute syntax is 
quite verbose and that it embeds one language inside another, which I 
can agree with to some extent. However, for the reasons enumerated 
above, plus the popular recommendation that style information be 
ommitted from the HTML document completely, I don't think that HTML can 
feasibly be altered the way you describe.
Received on Tuesday, 17 July 2007 07:00:29 UTC

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