W3C home > Mailing lists > Public > public-vocabs@w3.org > December 2011

Re: Syntax for itemprop breadcrumb

From: Gregg Kellogg <gregg@kellogg-assoc.com>
Date: Sat, 17 Dec 2011 14:20:27 -0500
To: Jason Douglas <jasondouglas@google.com>
CC: John Panzer <jpanzer@google.com>, Jeni Tennison <jeni@jenitennison.com>, public-vocabs <public-vocabs@w3.org>, Tim van Oostrom <tim@depulz.nl>, Aaron Bradley <aaranged@yahoo.com>
Message-ID: <64746D85-8278-49DB-B9A6-E5BA5FA3587E@kellogg-assoc.com>
On Dec 17, 2011, at 10:18 AM, Jason Douglas wrote:

> On Sat, Dec 17, 2011 at 9:00 AM, Gregg Kellogg <gregg@kellogg-assoc.com> wrote:
> Interesting that this is one place where RDFa @rel does what you want.
> 
> I was under the impression @rel was still allowed in RDFa Lite, just not required.  Named links seems like a use case where it does make things simpler.

Technically, RDFa Lite is just a publishing profile, which limits the available properties. However, processors need to accept all of RDFa 1.1 Core plus the relevant host language (HTML+RDFa 1.1), so any use of @rel, @datatype, @resource and other properties, will (MUST) work properly.

RDFa Lite is really intended to allow people to use simple markup to do simple things, and I expect the schema.org examples to show this. More complex things may require "power tools", and HTML+RDFa can convey the full expressiveness of other RDF serializations.

Gregg

>  
> It also requires @inlist to maintain the breadcrumb order.
> 
> RDFa Lite will have the same restrictions as microdata, requiring a @property on each <a> and depend on the vocabulary-specific handling of schema:breadcrumb to maintain order in RDF.
> 
> Gregg Kellogg
> Sent from my iPhone
> 
> On Dec 17, 2011, at 7:43 AM, "John Panzer" <jpanzer@google.com> wrote:
> 
>> For my parser, (c) appears to be the answer today.
>> 
>> On Dec 17, 2011 12:30 AM, "Jeni Tennison" <jeni@jenitennison.com> wrote:
>> Hi,
>> 
>> Just to point out that in something like:
>> 
>> <div itemprop="breadcrumb">
>>  <a href="category/books.html">Books</a> >
>>  <a href="category/books-literature.html">Literature & Fiction</a> >
>>  <a href="category/books-classics">Classics</a>
>> </div>
>> 
>> the 'breadcrumb' property actually takes the value "Books > Literature & Fiction > Classics" (whitespace normalised for brevity). So whether or not they have <a> elements wrapped around individual words doesn't matter: a conformant microdata processor won't see them anyway.
>> 
>> I've raised this before, but it is still not clear to me whether
>> 
>> a. schema.org consumers only want that plain text string;
>> b. schema.org consumers are preserving the HTML content (contrary to the microdata spec); or
>> c. the examples are wrong and the itemprop should be on individual breadcrumb items
>> 
>> Cheers,
>> 
>> Jeni
>> 
>> On 16 Dec 2011, at 23:30, Aaron Bradley wrote:
>> 
>> >
>> >
>> > Thanks for weighing in, Tom.
>> >
>> > In this case, though, all the examples explicitly show all breadcrumb links belonging to one itemprop - what they omit is an additional, unlinked "breadcrumb" component.
>> >
>> > See on http://schema.org/WebPage:
>> >
>> > <div itemprop="breadcrumb">
>> >   <a href="category/books.html">Books</a> >
>> >   <a href="category/books-literature.html">Literature & Fiction</a> >
>> >   <a href="category/books-classics">Classics</a>
>> > </div>
>> >
>> >
>> > By the way, the separate page identifier in the <h1> I wouldn't have a problem handling (it's not a breadcrumb) - it's the additional component on the same line.  E.g. (and this is the syntax I'm leaning towards - *not* including the unlinked item in the breadcrumb declaration):
>> >
>> >
>> > <div>
>> >
>> > <span itemprop="breadcrumb">
>> >   <a href="category/books.html">Books</a> >
>> >   <a href="category/books-literature.html">Literature & Fiction</a> >
>> >   <a href="category/books-classics">Classics</a></span> >
>> >   Boring Classics
>> > </div>
>> > <h1>Boring Classics</h1>
>> >
>> >
>> > ----- Original Message -----
>> >> From: Tim van Oostrom <tim@depulz.nl>
>> >> To: public-vocabs@w3.org
>> >> Cc:
>> >> Sent: Friday, December 16, 2011 2:26:37 PM
>> >> Subject: Re: Syntax for itemprop breadcrumb
>> >>
>> >> Hi Aaron,
>> >> I personally interpreted breadcrumb like:
>> >>
>> >> <div itemscope itemtype="http://schema.org/Thing";>
>> >>    <a href="category/books.html"
>> >> itemprop="breadcrumb">Books</a>  >
>> >>    <a href="category/books-literature.html"
>> >> itemprop="breadcrumb">Literature&  Fiction</a>  >
>> >>    <a href="category/books-classics"
>> >> itemprop="breadcrumb">Classics</a>  >
>> >>    Boring Classics
>> >> <h1 itemprop="name">Boring Classics</h1>
>> >>   </div>
>> >>
>> >>
>> >> 1 breadcrumb per Item/Link (semantically more obvious and less work to
>> >> determine what is what?)
>> >>
>> >> You'd have a list of breadcrumb(s). This should however be an ordered list.
>> >>
>> >> - Tim
>> >>
>> >>>   In breadcrumb display, the unlinked current page or section is often
>> >> displayed in the same line as the linked parents.  E.g.:
>> >>>
>> >>>   <div><a href="/">Home</a>  | About
>> >> us</div>
>> >>>
>> >>>   Should this unlinked portion be ("About us" in the example above)
>> >> be included in the breadcrumb itemprop or excluded from it? 1 or 2 below?
>> >>>
>> >>>
>> >>>   1 - Unlinked portion part of breadcrumb itemprop
>> >>>
>> >>>   <div itemprop="breadcrumb">
>> >>>     <a href="category/books.html">Books</a>  >
>> >>>     <a
>> >> href="category/books-literature.html">Literature&
>> >> Fiction</a>  >
>> >>>     <a href="category/books-classics">Classics</a>
>> >>>
>> >>>     Boring Classics
>> >>>   </div>
>> >>>
>> >>>   2 - Unlinked portion not a part of breadcrumb itemprop
>> >>>
>> >>>   <div>
>> >>>   <span itemprop="breadcrumb">
>> >>>     <a href="category/books.html">Books</a>  >
>> >>>     <a
>> >> href="category/books-literature.html">Literature&
>> >> Fiction</a>  >
>> >>>     <a
>> >> href="category/books-classics">Classics</a></span>
>> >>>
>> >>>     Boring Classics
>> >>>   </div>
>> >>>
>> >>>   None of the schema.org examples show this use case.
>> >>>
>> >>>   See also this same question on a G+ post - feel free to comment there.
>> >>>   https://plus.google.com/106943062990152739506/posts/Bf5ZYWkVtM1
>> >>>
>> >>>   Thanks,
>> >>>   Aaron
>> >>>
>> >>>
>> >>>
>> >>
>> >
>> >
>> 
>> --
>> Jeni Tennison
>> http://www.jenitennison.com
>> 
>> 
> 
Received on Saturday, 17 December 2011 19:21:06 GMT

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