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XHTML+RDFa (Extensible Hypertext Markup Language + Resource Description Framework in attributes) is an extended version of the XHTML markup language for supporting RDF through a collection of attributes and processing rules in the form of well-formed XML documents. XHTML+RDFa is one of the techniques used to develop Semantic Web content by embedding rich semantic markup. Version 1.1 of the language is a superset of XHTML 1.1 , integrating the attributes according to RDFa Core 1.1. In other words, it is an RDFa support through XHTML Modularization .

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39-457: RDFa in XHTML version 1.0 became a World Wide Web Consortium (W3C) Recommendation on 14 October 2008. The current recommendation is RDFa + XHTML version 1.1, which became a W3C Recommendation on 7 June 2012 and was updated with a ”Second Edition” on 22 August 2013 and a ”Third Edition” on 17 March 2015. Version 1.1 is based on XHTML™ 1.1 - Module-based XHTML - Second Edition . Version 1.0

78-485: A bridge between the "human and data webs". The potential in web documents enriched with RDFa is increasing since major search engines begin to process them while indexing. Yahoo indexes RDFa and microformats since 2008 and Google since 2009. The RDFa attribute specifications make it possible to describe structured data in any markup language . The RDFa markup in XHTML+RDFa reuses the markup code , thus eliminating

117-753: A community of major web players and publishers to establish a MediaWiki wiki that seeks to document open web standards called the WebPlatform and WebPlatform Docs. In January 2013, Beihang University became the Chinese host. In 2022 the W3C WebFonts Working Group won an Emmy Award from the National Academy of Television Arts and Sciences for standardizing font technology for custom downloadable fonts and typography for web and TV devices. On 1 January 2023, it reformed as

156-586: A document entitled RDFa in XHTML: Syntax and Processing . This superseded and expanded upon the April draft; it contained rules for creating an RDFa parser, as well as guidelines for organizations wishing to make practical use of the technology. In October 2008 RDFa 1.0 reached recommendation status. RDFa 1.1 reached recommendation status in June 2012. It differs from RDFa 1.0 in that it no longer relies on

195-610: A new edition or level of the recommendation. Additionally, the W3C publishes various kinds of informative notes which are to be used as references. Unlike the Internet Society and other international standards bodies, the W3C does not have a certification program. The W3C has decided, for now, that it is not suitable to start such a program, owing to the risk of creating more drawbacks for the community than benefits. In January 2023, after 28 years of being jointly administered by

234-462: A public-interest 501(c)(3) non-profit organization . W3C develops technical specifications for HTML5 , CSS , SVG , WOFF , the Semantic Web stack , XML , and other technologies. Sometimes, when a specification becomes too large, it is split into independent modules that can mature at their own pace. Subsequent editions of a module or specification are known as levels and are denoted by

273-597: A set of core principles and components that are chosen by the consortium. It was originally intended that CERN host the European branch of W3C; however, CERN wished to focus on particle physics , not information technology . In April 1995, the French Institute for Research in Computer Science and Automation became the European host of W3C, with Keio University Research Institute at SFC becoming

312-570: A similar way to the href attribute, but without defining a hyperlink. Further into the paragraph, a span element containing an about attribute defines the book as another resource to specify metadata about. The book title and author are defined within the contents of this tag using the dc:title and dc:creator properties. Here are the same triples when the above document is automatically converted to RDF/XML : The above example can be expressed without XML namespaces in HTML5 : Note how

351-462: A working draft (WD) for review by the community. A WD document is the first form of a standard that is publicly available. Commentary by virtually anyone is accepted, though no promises are made with regard to action on any particular element commented upon. At this stage, the standard document may have significant differences from its final form. As such, anyone who implements WD standards should be ready to significantly modify their implementations as

390-533: Is an example of adding Dublin Core metadata to an XML element in an XHTML file. Dublin Core data elements are data typically added to a book or article (title, author, subject etc.) Moreover, RDFa allows the passages and words within a text to be associated with semantic markup: The following is an example of a complete XHTML+RDFa 1.0 document. It uses Dublin Core and FOAF , an ontology for describing people and their relationships with other people and things: In

429-482: Is available to assistive technology . There is a growing number of tools for better usage of RDFa vocabularies and RDFa annotation. Simplified approaches to semantically annotate information items in webpages were greatly encouraged by the HTML+RDFa (released in 2008) and microformats (since ~2005) standards. As of 2013 these standards were encoding events, contact information, products, and so on. Despite

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468-597: Is claimed to be an example markup language . The Document Type Definition (DTD) is published at the W3C website. According to the document type declaration , the identifiers of an XHTML+RDFa document should look like the following: An example XHTML+RDFa document: The RDFa metadata is embedded as an XHTML attribute of the document element, generally the XHTML tag. The annotation syntax provided by RDFa can be used to express RDF statements in XHTML documents. XHTML+RDFa documents can be validated individually online at

507-403: Is done by external experts in the W3C's various working groups. The Consortium is governed by its membership. The list of members is available to the public. Members include businesses, nonprofit organizations, universities, governmental entities, and individuals. Membership requirements are transparent except for one requirement: An application for membership must be reviewed and approved by

546-528: Is generally assumed that RDFa was originally intended only for XHTML 2, in fact the purpose of RDFa was always to provide a way to add a metadata to any XML-based language. Indeed, one of the earliest documents bearing the RDF/A Syntax name has the sub-title A collection of attributes for layering RDF on XML languages . The document was written by Mark Birbeck and Steven Pemberton , and was made available for discussion on October 11, 2004. In April 2007

585-462: Is minimal subset of RDFa ... consisting of a few attributes that may be used to express machine-readable data in Web documents like HTML, SVG, and XML. While it is not a complete solution for advanced data markup tasks, it does work for most day-to-day needs and can be learned by most Web authors in a day. RDFa Lite consists of five attributes: vocab, typeof, property, resource, and prefix. RDFa 1.1 Lite

624-555: Is now endorsed by the W3C, indicating its readiness for deployment to the public, and encouraging more widespread support among implementors and authors. Recommendations can sometimes be implemented incorrectly, partially, or not at all, but many standards define two or more levels of conformance that developers must follow if they wish to label their product as W3C-compliant. A recommendation may be updated or extended by separately-published, non-technical errata or editor drafts until sufficient substantial edits accumulate for producing

663-569: Is the main international standards organization for the World Wide Web . Founded in 1994 and led by Tim Berners-Lee , the consortium is made up of member organizations that maintain full-time staff working together in the development of standards for the World Wide Web. As of 5 March 2023, W3C had 462 members. W3C also engages in education and outreach, develops software and serves as an open forum for discussion about

702-571: Is the version of a standard that has passed the prior two levels. The users of the standard provide input. At this stage, the document is submitted to the W3C Advisory Council for final approval. While this step is important, it rarely causes any significant changes to a standard as it passes to the next phase. This is the most mature stage of development. At this point, the standard has undergone extensive review and testing, under both theoretical and practical conditions. The standard

741-721: Is upwards compatible with RDFa 1.1. In 2009 the W3C was positioned to retain RDFa Lite as unique and definitive standard alternative to Microdata . The position was confirmed with the publication of the HTML5 Recommendation in 2014. The essence of RDFa is to provide a set of attributes that can be used to carry metadata in an XML language (hence the 'a' in RDFa). These attributes are: There are five "principles of interoperable metadata" met by RDFa. Additionally RDFa may benefit web accessibility as more information

780-1040: The MIT Computer Science and Artificial Intelligence Laboratory (located in Stata Center ) in the United States, the (in Sophia Antipolis , France), Keio University (in Japan) and Beihang University (in China), the W3C incorporated as a legal entity, becoming a public-interest not-for-profit organization . The W3C has a staff team of 70–80 worldwide as of 2015 . W3C is run by a management team which allocates resources and designs strategy, led by CEO Jeffrey Jaffe (as of March 2010), former CTO of Novell . It also includes an advisory board that supports strategy and legal matters and helps resolve conflicts. The majority of standardization work

819-874: The W3C Markup Validation Service or together with CSS and RSS at W3C Unicorn . The validity of XHTML+RDFa documents can be indicated by the XHTML+RDFa conformance icons of W3C . XHTML syntax, additional namespaces and semantic markup. RDFa RDFa or Resource Description Framework in Attributes is a W3C Recommendation that adds a set of attribute-level extensions to HTML , XHTML and various XML-based document types for embedding rich metadata within Web documents. The Resource Description Framework (RDF) data-model mapping enables its use for embedding RDF subject-predicate-object expressions within XHTML documents. It also enables

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858-478: The dc:creator property (in the meta element) tells us who created the document. The hyperlink to the Einstürzende Neubauten website contains rel="foaf:interest" , suggesting that John Doe is interested in this band. The URI of their website is a resource. The foaf:interest inside the second p element is referring to a book by ISBN. The resource attribute defines a resource in

897-425: The vCard semantics (only basic items of person and organization annotations) dominance, and some cloning of annotations along the same domain , the counting of webpages (URLs) and domains with annotations is an important statistical indicator for usage of semantically annotated information in the Web. The statistics of 2017 show that usage of HTML+RDFa is now less than that of Microformats. The following

936-686: The Asian host in September 1996. Starting in 1997, W3C created regional offices around the world. As of September 2009, it had eighteen World Offices covering Australia, the Benelux countries (Belgium, Netherlands and Luxembourg), Brazil, China, Finland, Germany, Austria, Greece, Hong Kong, Hungary, India, Israel, Italy, South Korea, Morocco, South Africa, Spain, Sweden, and, as of 2016, the United Kingdom and Ireland. In October 2012, W3C convened

975-523: The W3C standards. RDFa was defined in 2008 with the "RDFa in XHTML: Syntax and Processing" Recommendation. Its first application was to be a module of XHTML . The HTML applications remained, "a collection of attributes and processing rules for extending XHTML to support RDF" expanded to HTML5, are now expressed in a specialized standard, the "HTML+RDFa" (the last is "HTML+RDFa 1.1 - Support for RDFa in HTML4 and HTML5" ). The "HTML+RDFa" syntax of 2008

1014-453: The W3C started considering adding DRM -specific Encrypted Media Extensions (EME) to HTML5 , which was criticised as being against the openness, interoperability, and vendor neutrality that distinguished websites built using only W3C standards from those requiring proprietary plug-ins like Flash . On 18 September 2017, the W3C published the EME specification as a recommendation, leading to

1053-522: The W3C. Many guidelines and requirements are stated in detail, but there is no final guideline about the process or standards by which membership might be finally approved or denied. The cost of membership is given on a sliding scale, depending on the character of the organization applying and the country in which it is located. Countries are categorized by the World Bank 's most recent grouping by gross national income per capita. In 2012 and 2013,

1092-836: The Web. The World Wide Web Consortium (W3C) was founded in 1994 by Tim Berners-Lee after he left the European Organization for Nuclear Research ( CERN ) in October 1994. It was founded at the Massachusetts Institute of Technology (MIT) Laboratory for Computer Science with support from the European Commission , and the Defense Advanced Research Projects Agency , which had pioneered the ARPANET ,

1131-432: The XHTML 2 Working Group produced a module to support RDF annotation within the XHTML 1 family. As an example, it included an extended version of XHTML 1.1 dubbed XHTML+RDFa 1.0 . Although described as not representing an intended direction in terms of a formal markup language from the W3C, limited use of the XHTML+RDFa 1.0 DTD did subsequently appear on the public Web. October 2007 saw the first public Working Draft of

1170-498: The XML-specific namespace mechanism. Therefore, it is possible to use RDFa 1.1 with non-XML document types such as HTML 4 or HTML 5. Details can be found in an appendix to HTML 5. An additional RDFa 1.1 Primer document was last updated 17 March 2015. (The first public Working Draft dates back to 10 March 2006. ) There are some main well-defined variants of the basic concepts, that are used as reference and as abbreviation to

1209-417: The example above, the document URI can be seen as representing an HTML document, but the document URI plus the "#me" string http://example.org/john-d/#me represents the actual person, as distinct from a document about them. The foaf:primaryTopic in the header tells us a URI of the person the document is about. The foaf:nick property (in the first span element) contains a nickname for this person, and

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1248-525: The extraction of RDF model triples by compliant user agents . The RDFa community runs a wiki website to host tools, examples, and tutorials. RDFa was first proposed by Mark Birbeck in the form of a W3C note entitled XHTML and RDF , which was then presented to the Semantic Web Interest Group at the W3C's 2004 Technical Plenary. Later that year the work became part of the sixth public Working Draft of XHTML 2.0. Although it

1287-455: The first integer in the title (e.g. CSS3 = Level 3). Subsequent revisions on each level are denoted by an integer following a decimal point (for example, CSS2.1 = Revision 1). The W3C standard formation process is defined within the W3C process document, outlining four maturity levels through which each new standard or recommendation must progress. After enough content has been gathered from 'editor drafts' and discussion, it may be published as

1326-729: The most direct predecessor to the modern Internet . It was located in Technology Square until 2004, when it moved, with the MIT Computer Science and Artificial Intelligence Laboratory, to the Stata Center. The organization tries to foster compatibility and agreement among industry members in the adoption of new standards defined by the W3C. Incompatible versions of HTML are offered by different vendors, causing inconsistency in how web pages are displayed. The consortium tries to get all those vendors to implement

1365-456: The need for unnecessary duplications. XHTML+RDFa is not widely distributed yet, probably due to the lack of support in authoring tools and content management systems . However, there is good tendency. Drupal 7, for example, supports RDFa . Since the “a” in RDFa stands for attributes, it is straightforward to use CSS selectors to style the code. The combination of XHTML 1.1 and RDFa modules

1404-407: The prefix foaf is still used without declaration. RDFa 1.1 automatically includes prefixes for popular vocabularies such as FOAF. The minimal document is: That is, it is recommended that all of these attributes are used: vocab , typeof , property ; not only one of them. RDFa Structured Data Example Person Schema in RDFa. W3C The World Wide Web Consortium ( W3C )

1443-622: The standard matures. A candidate recommendation is a version of a more mature standard than the WD. At this point, the group responsible for the standard is satisfied that the standard meets its goal. The purpose of the CR is to elicit aid from the development community on how implementable the standard is. The standard document may change further, but significant features are mostly decided at this point. The design of those features can still change due to feedback from implementors. A proposed recommendation

1482-487: Was also termed "RDFa 1.0" , so, there is no "RDFa Core 1.0" standard. In general this 2008's RDFa 1.0 is used with the old XHTML standards (as long as RDFa 1.1 is used with XHTML5 and HTML5). Is the first generic (for HTML and XML) RDFa standard; the "RDFa Core 1.1" is in the Third Edition, since 2015. RDFa Lite is a W3C Recommendation (1.0 and 1.1) since 2009, where it is described as follows: RDFa Lite

1521-607: Was based on the first edition. Conventional Web documents contain large amounts of structured data that can be rendered in web browsers . This approach works fine for publishing purposes, however, a large amount of data stored in Web documents cannot be processed this way. XHTML+RDFa can provide machine-readable metadata within the markup code which makes additional user functionalities available. Most important of all, actions can be performed automatically that enables up-to-date publishing, structured search and sharing. RDFa can serve as

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