Microdata is part of the WHATWG (Web Hypertext Application Technology Working Group) HTML Standard and is used to nest metadata within existing content on web pages. Search engines and web crawlers can extract and process microdata from a web page and use it to provide a richer browsing experience for users. Search engines benefit greatly from direct access to this structured data because it allows search engines to understand the information on web pages and provide more relevant results to users. Microdata uses a supporting vocabulary to describe an item and name-value pairs to assign values to its properties. Microdata is an attempt to provide a simpler way of annotating HTML elements with machine-readable tags than the similar approaches of using RDFa and classic micro-formats.
At a high level, microdata consists of a group of name-value pairs. The groups are called items, and each name-value pair is a property. Items and properties are represented by regular elements.
- To create an item, the attribute is used.
- To add a property to an item, the attribute is used on one of the item’s descendants.
Vocabularies
Google and other major search engines support the Schema.org (schema markup) vocabulary for structured data.
Schema markup is code you can add to your website that helps search engines return better results for users. Essentially, it gives vital information to search engines to include in your listing that can improve visibility online, as well as click-through rates.
In 2011, top search engines including Google, Yahoo, Bing, and Yandex collaborated to create schema.org, which is a “collaborative, community activity with a mission to create, maintain, and promote schemas for structured data on the Internet, on web pages, in email messages, and beyond.”
…schema markup will create an enhanced description — sometimes referred to as a rich snippet — which will appear in search results.
schema.org
This vocabulary defines a standard set of type names and property names, for example, Schema.org Music Event indicates a concert performance, with startDate and location properties to specify the concert’s key details. In this case, Schema.org Music Event would be the URL used by and startDate and location would be ’s that Schema.org Music Event defines.
Note: More about attributes can be found at http://schema.org/Thing.
Microdata vocabularies provide the semantics or meaning of an Item. Web developers can design a custom vocabulary or use vocabularies available on the web, such as the widely used schema.org vocabulary. A collection of commonly used markup vocabularies are provided by Schema.org.
Commonly used vocabularies:
- Creative works: CreativeWork, Book, Movie, MusicRecording, Recipe, TVSeries
- Embedded non-text objects: AudioObject, ImageObject, VideoObject
- Event
- Health and medical types: Notes on the health and medical types under MedicalEntity
- Organization
- Person
- Place, LocalBusiness, Restaurant
- Product, Offer, AggregateOffer
- Review, AggregateRating
- Action
- Thing
- Intangible
Major search engine operators like Google, Microsoft, and Yahoo! rely on the schema.org vocabulary to improve search results. For some purposes, an ad-hoc vocabulary is adequate. For others, a vocabulary will need to be designed. Where possible, authors are encouraged to re-use existing vocabularies, as this makes content re-use easier.
Localization
In some cases, search engines covering specific regions may provide locally-specific extensions of microdata. For example, Yandex, a major search engine in Russia, supports microformats such as hCard (company contact information), hRecipe (food recipe), hReview (market reviews) and hProduct (product data) and provides its own format for the definition of the terms and encyclopedic articles. This extension was made to solve transliteration problems between the Cyrillic and Latin alphabets. Due to the implementation of additional marking parameters of Schema’s vocabulary, the indexation of information in Russian-language web-pages became considerably more successful.
Global attributes
itemid – The unique, global identifier of an item.
– Used to add properties to an item. Every HTML element may have an attribute specified, where an consists of a name and value pair.
itemref – Properties that are not descendants of an element with the attribute can be associated with the item using an itemref. Itemref provides a list of element ids (not itemids) with additional properties elsewhere in the document.
– Itemscope (usually) works along with to specify that the HTML contained in a block is about a particular item. creates the Item and defines the scope of the associated with it. is a valid URL of a vocabulary (such as schema.org) that describes the item and its properties context.
– Specifies the URL of the vocabulary that will be used to define ’s (item properties) in the data structure. Itemscope is used to set the scope of where in the data structure the vocabulary set by will be active.
How to mark up your content using microdata(examples)
Why use microdata?
Your web pages have an underlying meaning that people understand when they read the web pages. But search engines have a limited understanding of what is being discussed on those pages. By adding additional tags to the HTML of your web pages—tags that say, “Hey search engine, this information describes this specific movie, or place, or person, or video”—you can help search engines and other applications better understand your content and display it in a useful, relevant way. Microdata is a set of tags, introduced with HTML5, that allows you to do this.
a. and :
Let’s start with a concrete example. Imagine you have a page about the movie Avatar—a page with a link to a movie trailer, information about the director, and so on. Your HTML code might look something like this:
<div>
<h1>Avatar</h1>
<span>Director: James Cameron (born August 16, 1954)</span>
<span>Science fiction</span>
<a href="../movies/avatar-theatrical-trailer.html">Trailer</a>
</div>
To begin, identify the section of the page that is “about” the movie Avatar. To do this, add the element to the HTML tag that encloses information about the item, like this:
<div >
<h1>Avatar</h1>
<span>Director: James Cameron (born August 16, 1954) </span>
<span>Science fiction</span>
<a href="../movies/avatar-theatrical-trailer.html">Trailer</a>
</div>
By adding , you are specifying that the HTML contained in the <div>...</div> block is about a particular item.
But it’s not all that helpful to specify that there is an item being discussed without specifying what kind of an item it is. You can specify the type of item using the attribute immediately after the .
<div >
<h1>Avatar</h1>
<span>Director: James Cameron (born August 16, 1954)</span>
<span>Science fiction</span>
<a href="../movies/avatar-theatrical-trailer.html">Trailer</a>
</div>This specifies that the item contained in the div is in fact a Movie, as defined in the schema.org type hierarchy. Item types are provided as URLs, in this case http://schema.org/Movie.
b.
What additional information can we give search engines about the movie Avatar? Movies have interesting properties such as actors, director, ratings. To label properties of an item, use the attribute. For example, to identify the director of a movie, add to the element enclosing the director’s name. (There’s a full list of all the properties you can associate with a movie at http://schema.org/Movie.)
<div ="http://schema.org/Movie">
<h1 >Avatar</h1>
<span>Director: <span >James Cameron</span> (born August 16, 1954)</span>
<span >Science fiction</span>
<a href="../movies/avatar-theatrical-trailer.html" >Trailer</a>
</div>Note that we have added additional <span>...</span> tags to attach the attributes to the appropriate text on the page. <span> tags don’t change the way pages are rendered by a web browser, so they are a convenient HTML element to use with .
Search engines can now understand not just that http://www.avatarmovie.com is a URL, but also that it’s the URL for the trailer for the science-fiction movie Avatar, which was directed by James Cameron.
c. Embedded items
Sometimes the value of an item property can itself be another item with its own set of properties. For example, we can specify that the director of the movie is an item of type Person and the Person has the properties name and birthDate. To specify that the value of a property is another item, you begin a new immediately after the corresponding .
<div ="http://schema.org/Movie">
<h1 >Avatar</h1>
<div >
Director: <span >James Cameron</span> (born <span >August 16, 1954</span>)
</div>
<span >Science fiction</span>
<a href="../movies/avatar-theatrical-trailer.html" >Trailer</a>
</div>Learn More
Structured Data Markup Helper from Google
Schema.org is a collaborative, community activity with a mission to create, maintain, and promote schemas for structured data on the Internet, on web pages, in email messages, and beyond.
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