Microformat

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Microformats are a markup format for semantic annotation of HTML or XHTML . Fine structuring carried out using microformat annotation can easily be extracted from web pages and make the meaning of the page content understandable to other programs (such as search engines ) without changing it.

Each microformat was developed for a specific topic or area of ​​knowledge. There are microformats for appointments, contact information and social relationships .

microformats logo

Examples

The (X) HTML standards that have existed to date allow minimal semantic annotations through the following attributes :

rel
(from relationship ) Forward relationship in an anchor element (<a href=... rel=...> ... </a>), description of the target address
rev
(from reverse relationship ) Backward relationship , opposite of the forward relationship , description of the referencing document. (Obsolete since HTML5)
class
assigns a class name or a set of class names to an element
Example: normally contact information in HTML is presented as simple elements:
 <div>
   <div>Max Mustermann</div>
   <div>Musterfirma</div>
   <div>01234/56789</div>
   <a href="http://example.com/">http://example.com/</a>
 </div>
The following source text is marked with the microformat hCard and integrated as class = "vcard":
 <div class="vcard">
   <div class="fn">Max Mustermann</div>
   <div class="org">Musterfirma</div>
   <div class="tel">01234/56789</div>
   <a class="url" href="http://example.com/">http://example.com/</a>
 </div>
Specific classattributes are used here for the name (fn), the organization (org), the telephone number (tel) and the Internet address ( url ).
So it is a software, z. B. browser plug-ins or search engines , it is possible to read out the information and transfer it to other applications such as address books or route planners .

In the example text “The meeting point is at 24.31 , -14.09 ” it is understandable from the context that it is a pair of coordinates. By tagging this data with HTML class names, software agents are able to recognize the values ​​and process them further, for example to export them to a GPS device or to display the coordinates on a map.

This example uses the class names h-geo, p-latitudeand of p-longitudethe Geo microformat . 

 Der Treffpunkt befindet sich bei: 
   <span class="h-geo geo">
     <span class="p-latitude latitude">24.31</span>,
     <span class="p-longitude longitude">-14.09</span>
   </span>

Note: The class names geo, latitudeand longitudeare also recites, for backward compatibility.

Classification

Microformats can be divided into two groups: elementary and composite formats. The elementary microformats include rel-license , rel-nofollow (identifies a link that should not be used to calculate the link popularity of the linked page), rel-tag , XFN and XOXO . Compound microformats build on the elementary and can solve more complex and extensive tasks. The composite microformats include geo , hCalendar (for labeling calendar and event data ), hCard (for labeling contact information, referred to as vcard in HTML code ) and xFolk .

distribution

Microformats emerged around 2005 in an effort to make relevant data both machine-readable and directly readable for users. Dan Cederholm and Tantek Çelik founded the microformats.org project on June 20, 2005 for dissemination . The impetus was provided by Technorati , which deals with search engine technology and also operates the kitchen.technorati.com search engine for microformats.

There are browser plug-ins for various browsers such as Firefox , Chrome , Internet Explorer and Safari that can evaluate individual microformats.

A common microformat is nofollow . There are now numerous tools that support authors with labeling with microformats.

Alternatives

RDFa is a similar approach in which RDF (the Resource Description Framework known from the semantic web for annotating any resources) is embedded in (X) HTML. However, the (X) HTML syntax has been expanded slightly for this purpose. RDFa is a little more difficult to write than microformats, but more expressive because you are not limited to certain subject areas, but can describe things from all areas using suitable ontologies .

Microdata is an alternative to the microformat developed by WHATWG . Microdata does not provide any semantics; H. Web developers can use their own vocabulary. However, the use of an established vocabulary is advocated as it simplifies content reuse.

literature

  • John Allsopp: Microformats: empowering your markup for Web 2.0 . Friendsof, Berkeley, California 2007, ISBN 978-1-59059-814-6 .
  • Florian Beer: Microformats - semantics for everyone: The semantic web and how microformats will drive development . VDM Verlag, Vienna, Austria 2008, ISBN 978-3-8364-9221-8 .
  • Florence Maurice: Microformats - semantics for websites . developer.press, Munich, Germany 2009, ISBN 978-3-86802-017-5 .

Web links

Individual evidence

  1. ↑ a b c Carsten M. Schulze: What are microformats and what do you need them for? - in: Patrick Danowski and Julia Bergmann (eds.): Handbuch Bibliothek 2.0, de Gruyter 2010, ISBN 311023209X , p. 129ff.
  2. ↑ Microformats - extension of HTML
  3. ↑ microformats.org