On 11/01/10 6:40 PM, Boris Zbarsky wrote:
On 1/11/10 1:24 AM, Sean Hogan wrote:
That's correct. jQuery's $(element).find("div") is the equivalent of
SelectorsAPI2's element.querySelectorAll(":scope div") or
So in fact jquery can simply implement Element.find in terms of
querySelectorAll by just prepending ":scope " to the selector string,
right? Note that this happens to work even for the "> div" case (by
converting the selector to ":scope > div", which is what jquery means).
So the "> div" thing doesn't seem to require preparsing (modulo commas
in the selector; was that the key point?). Of course the jquery
selectors that aren't in CSS do (or possibly post-parsing depending on
how it's implemented).
If we could assume that commas only ever delimit selectors in a
selector-string, and if jQuery didn't support selectors not implemented
by the browser then something like the following conversion would be
sufficient for all jQuery queries:
function preprocess(str) { return ":scope " + str.split(",").join(",
:scope "); }
Hence no value is added by queryScopedSelector*().
If we can't assume those things then jQuery will still need its current
selector parser.
Hence no value is added by queryScopedSelector*().
My point is that jQuery's $(element).find("> div") isn't supported
(without pre-processing by the JS lib) by
element.queryScopedSelectorAll().
...
element.queryScopedSelectorAll(":scope > div") generally becomes
element.parentNode.querySelectorAll(":scope > div", element) which is
the same as
element.querySelectorAll(":scope > div", element) or even
element.querySelectorAll(":scope > div")
That's what I'm confused about. Does implementing element.find(">
div") as element.queryScopedSelectorAll(":scope > div") not do what
the current jquery code does? If not, how do they differ?
They will select the same list of elements.
As will element.querySelectorAll(":scope > div")
I'm still confused about queryScopedSelectorAll, though. It sounds
from your example like queryScopedSelectorAll just prepends ":scope "
to the whole query string and then calls querySelectorAll on the
parentNode of the scope node, with the scope node passed in as the
optional argument. So:
element.queryScopedSelectorAll(myStr)
is the same as:
element.parentNode.querySelectorAll(":scope " + myStr, element);
is that correct?
For some selector-strings yes.
More specifically, the parsing rules for scoped selectors are at:
http://dev.w3.org/2006/webapi/selectors-api2/#parse-a-scoped-selector
Scoped selectors must still be valid selectors, so "> div", "+ div", "~
div" will all throw exceptions.
They must be explicitly written as ":scope > div", etc in the call to
element.queryScopedSelectorAll().
Thus the queryScopedSelectorAll call won't prepend them with ":scope ".
