Michael,
On using the is= syntax to base your new element on an existing
HTML element:
<ol is="simple-steps">
I am almost positive that you cannot put more than one
value in the is="". I know a couple people who were on the web
components committee, I can try to get a definitive answer. It's
probably in the spec somewhere too.
Mark Giffin
Mark Giffin Consulting, Inc.
http://markgiffin.com/
On 6/26/2016 5:56 PM, Michael Priestley wrote:
I talked a bit more
about it with Don,
and this is where my thinking is right now, based on the
descriptions of
custom elements here:
https://www.w3.org/TR/custom-elements/#custom-elements-autonomous-drawbacks
- our two main alternatives are
autonomous
custom elements, which we could give custom element names to
- or customized built-in
elements, which
would retain the name of an existing HTML element plus the "is"
attribute giving a custom element name
Example for autonomous custom
elements:
<simple-steps>
<simple-step>...</simple-step>
</simple-steps>
Pros:
- they have easily understandable
semantic
names
- they look like XML, and can
more closely
mimic XML specializations
Cons:
- nothing will happen remotely
resembling
fallback processing (like rendering these as an ordered list)
without a
bunch of _javascript_
- for an extended discussion of
how
sucky this can be, see https://www.w3.org/TR/custom-elements/#custom-elements-autonomous-drawbacks
Example for customized
built-in elements
<ol is="simple-steps">
<li
is="simple-step">...</li>
</ol>
Pros:
- they process automatically as
list
items
- they can be registered using
_javascript_
as special nodes, for extra behavior, but you only need to
identify the
delta stuff
Cons:
- looks less like XML
Net
My clear preference is now for
customized
built-in elements, given the warnings of the spec against using
autonomous
custom elements when extending an existing element type.
But the open question for me is
whether
the "is" attribute can take multiple values. If it can, it could
map really cleanly to specializations. Even the requirement for
hyphenation
in the element name could be a mirror for the "/" in the XML
class attribute.
Otherwise we'd be looking again
at limiting
ourselves to one level of specialization, which may still be on
the page
anyway - nobody has said they want it yet.
So... does anyone have a contact
on
the Web Platform Working Group? I couldn't find a simple answer
to my question
anywhere, including here:
https://lists.w3.org/Archives/Public/public-webapps/
If no one else has a contact I'll
poke
around IBM.
Michael Priestley, Senior Technical Staff Member (STSM)
Enterprise Content Technology Strategist
