Ian Hickson wrote:
On Fri, 23 Sep 2005, Sjoerd Visscher wrote:
These features would be nice for all methods that return NodeLists. As
NodeLists are live, adding a contains method, and a modification event
to the NodeList interface should cover all you need and much more.
The use cases for applying the selector apis to NodeLists aren't yet
clear. I have not added the feature to this version of the spec, but it
could be something worth considering in the future.
I discussed this on IRC [1]. For future reference, here's the chat log.
<Hixie> Lachy: i have a request here from someone suggesting the
query-by-selectors api should apply to all NodeList objects too
<Lachy> I'm not sure I could get it into this first version of the spec,
but it might be an interesting extension for the next revision
<Lachy> especially since we're starting to get implementations already,
I'd rather focus on getting interop with the current feature set
before piling on more
<annevk> how does it work on NodeList?
<Lachy> I assume it would evaluate each node in the list, in the context
of the document it's in
<Dashiva> So it's more like using the nodelist as a filter to the query
result
<Lachy> e.g. var list = document.getElementsByTagName("p");
var filteredList = list.querySelector("div>p");
<Lachy> so filteredList would contain all the p elements from list,
which are children of div elements in the document
<Lachy> not sure of the use case though, since
document.querySelector("div>p"); would do the same
<Hixie> yeah i dunno what the use case is exactly, though there are
other places that return NodeLists
<Lachy> I suppose that would have been sent before the webapi wg was
formed, and thus hadn't begun working on selectors api.
<Dashiva> By making querySelector work on nodelists, it would be
possible to chain querySelector calls too...
<Lachy> so that's why you wouldn't have forwarded it then
<Hixie> Lachy: yeah it ended up in the worng bucket
<Lachy> Dashiva, what's the point in chaining queryselector calls?
<Lachy> just chain the selctors and make one call
<Dashiva> Lachy: If you want to select something based on ancestors or
preceding siblings, CSS isn't very helpful
<Hixie> document.querySelector('a x').querySelector('b x') is equivalent
to 'a b x, b a x' which can get much more complex
<Lachy> Dashiva, I assume you meant if you want to select ancestors or
preceding siblings, rather than something based on those (since
selectors already work the way you said it)
<Dashiva> Yeah, that
<Dashiva> And Hixie seems to have found an even better case :)
<Hixie> it's a bit like having :matches(... #)
<Lachy> oh, right
<Lachy> it's worth thinking about, but definitely need to evaluate the
use cases and see how authors actually use these apis
[1] http://krijnhoetmer.nl/irc-logs/whatwg/20080415#l-831
--
Lachlan Hunt - Opera Software
http://lachy.id.au/
http://www.opera.com/
