W3C home > Mailing lists > Public > public-vocabs@w3.org > April 2014

working of schema.org/WebPage

From: Jason Douglas <jasondouglas@google.com>
Date: Thu, 17 Apr 2014 17:51:41 +0000
Message-ID: <CAEiKvUAR54q04Gn3k9bCZjGUHsG92DROUi2DV9r+fXtCmx-t0Q@mail.gmail.com>
To: Jarno van Driel <jarno@quantumspork.nl>, Public Vocabs <public-vocabs@w3.org>
It is legal for there to be multiple top-level entities.  That description
of WebPage is not meant to imply anything about the relationship of those
top-level objects... all that is saying is that if a relation is declared
without an explicit subject, then the subject will be assumed to be the
current WebPage.

That said, we probably do need a mechanism for indicating the "primary
entity" of a webpage when there is one.  Current clients make up their own
heuristics for this, but I think it would be better to have an explicit way
of stating that.

-jason


On Thu Apr 17 2014 at 10:41:47 AM, Jarno van Driel <jarno@quantumspork.nl>
wrote:

> I'm trying to understand semantic mechanisms better but am a bit confused
> about schema.org/WebPage and I'd like to know how it works.
>
> Now it could well be I understand certain terminologies wrong, so please
> bare with me and be so nice to correct me when needed.
>
> 1] The description of http://schema.org/WebPage says:
> "Every web page is implicitly assumed to be declared to be of type
> WebPage, so the various properties about that webpage, such as breadcrumb
> may be used. We recommend explicit declaration if these properties are
> specified, but if they are found outside of an itemscope, they will be
> assumed to be about the page."
>
> code example:
> <body itemscope itemtype="http://schema.org/WebPage">
>   <!-- Content -->
> </body>
>
> Now if the WebPage is the only entity is it then considered to be the
> 'Subject', the 'Object' or both?
>
> 2] If the WebPage contains an entity, let's say a Product, without
> specifying a property on the Product and I check this with Google's SDTT, I
> see 2 'root' entities, since there is no property to chain the two
> together. Yet I get the impression the Product gets treated as the
> 'Object', since it's the Product that gets used for Rich snippet
> extraction, and that therefore the WebPage is the 'Subject' :
>
> code example:
> <body itemscope itemtype="http://schema.org/WebPage">
>   <span itemprop="name">Page title</span>
>
>   <div itemscope itemtype="http://schema.org/Product">
>     <span itemprop="name">Product name</span>
>     <!-- Product properties -->
>   </div>
> </body>
>
> Now since "Every web page is implicitly assumed to be declared to be of
> type WebPage" I was wondering if there also is a property that is
> 'implicitly assumed to be declared' (something like @contains) on the first
> entity that comes after it, like Product in this case, which indicates that
> the Product is the 'Object'?
>
> And if not, than how does a parser 'know' which of the entities is the
> 'Subject' and which is the 'Object', shouldn't there be a predicate for
> this?
>
> 3] When a WebPage contains a bunch of 'root' entities, how does a parser
> make sense of this, does the DOM have anything to do with this?
>
> <body itemscope itemtype="http://schema.org/WebPage">
>   <span itemprop="name">Page title</span>
>
>   <div itemscope itemtype="http://schema.org/Product">
>     <span itemprop="name">Product 1 name</span>
>     <!-- Product properties -->
>   </div>
>
>   <div itemscope itemtype="http://schema.org/Product">
>     <span itemprop="name">Product 2 name</span>
>     <!-- Product properties -->
>   </div>
>
>   <div itemscope itemtype="http://schema.org/LocalBusiness">
>     <span itemprop="name">Business name</span>
>     <!-- Product properties -->
>   </div>
> </body>
>
> Now the above could be full of misunderstandings because I lack in
> theoretical knowledge still, but that's exactly the thing I'm hoping to
> change. Who can enlighten me?
>
>
>
>
>
>
Received on Thursday, 17 April 2014 17:52:10 UTC

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