[whatwg] [html5] Rendering of interactive content

Benjamin Hawkes-Lewis bhawkeslewis at googlemail.com
Sat Feb 7 11:24:53 PST 2009

On 7/2/09 18:51, Giovanni Campagna wrote:
>     So the rendering section imposes *no* requirements on HTML5
>     conforming user agents, therefore the spec is not "constraining the
>     implementation of HTML5 on that of XBL2".
> Yes, but UA that don't follow that set of CSS rules are not
> interoperable with UA that follow, ie scripts must detect what
> properties are ignored or defaulted.

HTML5 conforming UAs do not have to implement CSS or CSSOM.

CSSOM-implementing UAs do not have to do express all styling with CSS 

When they do, you can query for those properties via the CSSOM.

>     Furthermore, user agents are free to use any method they like to
>     mimic the suggested rendering, including CSS3 UI where applicable.
>     They don't have to use BE CSS at all.
> They're "expected" to use CSS, and I expect that, according to html5,
> "button { binding: initial; }" makes it like a <span>.

Is text I quoted not clear that the word "expected" is chosen precisely 
to make it clear that these are _not_ normative requirements? If so, 
could you suggest modifications to the text to make it even clearer?

>     If this is not obvious from the text, perhaps you would like to
>     suggest a change to the text that would make it clearer?
> I don't agree with rendering being "optional". If interoperability is so
> important (and it is), rendering should be normative.

How does that follow?

And what do you mean by "rendering should be normative"?

Are you suggesting, for example, that HTML5 should mandate unvisited 
links be blue and underlined in the screen medium unless set otherwise 
by a publisher stylesheet? That would prevent UAs providing a default 
presentation of semantic HTML that suits the end-user!

Note that would prevent UAs complying with W3C's user-agent 
accessibility guidelines:


Benjamin Hawkes-Lewis

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