On 7/2/09 20:07, Giovanni Campagna wrote:
Yes, but what properties should I query for?
In order to find out what, precisely?
Binding, behaviour, appearance, border, color, font, all in once? And what should their values be?
Their values depend on user agent defaults (which may be anything), user preferences (which may be anything), user stylesheets (which may be anything), and publisher styles (which may be anything), as per the CSS cascade:
http://www.w3.org/TR/CSS21/cascade.html#cascade In other words, the values cannot be known for sure until you query them.Even if you mandated precise user agent defaults, the values still could not be known for sure until you queried them, because of user preferences, user stylesheets, and publisher styles.
If <input type="submit"> in some UA is rendered with all properties set
to initial, not only it does not express the semantic of a button, but
it may be difficult for a user to actually recognize it as a button and
eventually click it.
In that case I, as the author, may need to manually
set { appearance:push-button; content:attr(value,string,"Send"); } in
order to have my form submitted.
Try this example (in Firefox or Safari):
data:text/html,<style>label { position:fixed; top:-1em; border:1px solid
black; } label input { -moz-appearance:none; -webkit-appearance:none;
border:none; width:auto; } input[type=submit] { -moz-appearance:none;
-webkit-appearance:none; background-color:transparent; border:none;
}</style><form action="http://www.google.com/search";
method="get"><label>Search: <input type="text" value=""
name="q"></label><input type=submit value="Go">
Imagine that was the UA default stylesheet instead of an author
stylesheet and you may see what interoperability means with web
application look and feel.
There's a recursion problem there.User agents may derive the effects of "appearance" from user-agent default stylesheets:
http://www.w3.org/TR/css3-ui/#appearanceIf the user agent default stylesheet does not style push buttons differently from other content, and the user agent derives the effects of appearance from that stylesheet, then checking or setting the value of appearance would not guarantee that your submit button would appear button-like.
HTML5 should not mandate the UA present <a>s in blue, but it should mandate the UA present <a>s like links (appearance:hyperlink).
How would you test whether a UA complied with that requirement or not? Purely by testing the value of the appearance property applied to the element with a default configuration?
Obviously this does not relate in any way with user preferences, here we talk about UA defaults.
What if a developer wants to create a UA reflecting a target market's differing preferences for presentation, rather than require the users to configure it first?
Are you proposing such a UA should be non-conforming? -- Benjamin Hawkes-Lewis
