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Re: working of schema.org/WebPage

From: Jocelyn Fournier <jocelyn.fournier@gmail.com>
Date: Thu, 17 Apr 2014 21:03:11 +0200
Message-ID: <5350256F.7090402@gmail.com>
To: Jason Douglas <jasondouglas@google.com>, Jarno van Driel <jarno@quantumspork.nl>
CC: Public Vocabs <public-vocabs@w3.org>
Le 17/04/2014 20:25, Jason Douglas a écrit :
> Yup, that's messed up.  Let's fix it!

Hi,

Note that examples regarding mainContentOfPage on schema.org are also 
misleading.
E.g. : http://schema.org/Table
=>  <meta itemprop="mainContentOfPage" content="true"/>

I would have expected
<div itemprop="mainContentOfPage" itemscope 
itemtype="http://schema.org/Table">


But I fully agree it would be much more usefull to have 
mainContentOfPage as a 'Thing' rather than 'WebPageElement'

   Jocelyn

>
> On Thu Apr 17 2014 at 11:15:43 AM, Jarno van Driel
> <jarno@quantumspork.nl <mailto:jarno@quantumspork.nl>> wrote:
>
>     "...if a relation is declared without an explicit subject, then the
>     subject will be assumed to be the current WebPage."
>     Got it.
>
>     "It is legal for there to be multiple top-level entities." +
>     "Current clients make up their own heuristics for this..."
>     Brainfreeze!
>     How am I, as a developer, to deal with this? Does this mean I have
>     to somehow figure out which heuristics every parser/search engine
>     uses, to be able to have control or do I need to try to chain
>     everything together such that only one top-level entity is left?
>
>     And how would I do this for a category page on for example an
>     eCommerce site. Which shows a range of Product entities on a
>     CollectionPage, which together form the main-content and where the
>     CollectionPage, for lack of a better term, only functions as a
>     'wrapper' for the list of products.
>
>     "we probably do need a mechanism for indicating the "primary entity"
>     of a webpage when there is one..."
>     One the reasons why I asked my questions is because I encounter
>     quite a lot of markup on websites where people use @mainContentPage
>     on entities like Product. Now @mainContentOfPage has the expected
>     type WebPageElement, but many aren't aware of this. And since there
>     is no property to indicate which entity is the primary one I
>     actually can completely understand they try to resolve it like this.
>     And frankly, I'm confused as well.
>
>
>
>     On Thu, Apr 17, 2014 at 7:51 PM, Jason Douglas
>     <jasondouglas@google.com <mailto:jasondouglas@google.com>> wrote:
>
>         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 <mailto:jarno@quantumspork.nl>> wrote:
>
>             I'm trying to understand semantic mechanisms better but am a
>             bit confused about schema.org/WebPage
>             <http://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 19:03:42 UTC

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