HTML has included semantic markup since its inception. In an HTML document, the author may, among other things, "start with a title; add headings and paragraphs; add emphasis to text; add images; add links to other pages; use various kinds of lists".
At one time, HTML also included presentational markup such as
tags. There are also the semantically neutral span and div tags. Since the late 1990s when Cascading Style Sheets were beginning to work in most browsers, web authors have been encouraged to avoid the use of presentational HTML markup with a view to the separation of presentation and content.
In 2001 Tim Berners-Lee participated in a discussion of the Semantic Web, where it was presented that intelligent software 'agents' might one day automatically trawl the Web and find, filter and correlate previously unrelated, published facts for the benefit of human users. Such agents are not commonplace even now, but some of the ideas of Web 2.0, mashups and price comparison websites may be coming close. The main difference between these web application hybrids and Berners-Lee's semantic agents lies in the fact that the current aggregation and hybridisation of information is usually designed in by web developers, who already know the web locations and the API semantics of the specific data they wish to mash, compare and combine.
An important type of web agent that does crawl and read web pages automatically, without prior knowledge of what it might find, is the Web crawler or search-engine spider. These software agents are dependent on the semantic clarity of web pages they find as they use various techniques and algorithms to read and index millions of web pages a day and provide web users with search facilities.
In order for search-engine spiders to be able to rate the significance of pieces of text they find in HTML documents, and also for those creating mashups and other hybrids, as well as for more automated agents as they are developed, the semantic structures that exist in HTML need to be widely and uniformly applied to bring out the meaning of published text.
While the true semantic web may depend on complex RDF ontologies and metadata, every HTML document makes its contribution to the meaningfulness of the Web by the correct use of headings, lists, titles and other semantic markup wherever possible. This "plain" use of HTML has been called "Plain Old Semantic HTML" or POSH. The correct use of Web 2.0 'tagging' creates folksonomies that may be equally or even more meaningful to many. HTML 5 will introduce several new semantic tags that will become commonplace in web documents of the future, such as
Presentational markup tags are not deprecated in current HTML (4.01) and XHTML recommendations, but were recommended against. In HTML 5 some of those elements, such as
b are still specified as their meaning has been clearly defined "as to be stylistically offset from the normal prose without conveying any extra importance".
Read more about this topic: Semantic HTML
Other articles related to "history":
... The Skeptical School of early Chinese history, started by Gu Jiegang in the 1920s, was the first group of scholars within China to seriously question the traditional story of its early history "the later the time ... early Chinese history is a tale told and retold for generations, during which new elements were added to the front end" ...
... History of Charles XII, King of Sweden (1731) The Age of Louis XIV (1751) The Age of Louis XV (1746–1752) Annals of the Empire – Charlemagne, A.D ... II 1763) History of the Parliament of Paris (1769) ...
... generally believed that gambling in some form or another has been seen in almost every society in history ... and Romans to Napoleon's France and Elizabethan England, much of history is filled with stories of entertainment based on games of chance ... In American history, early gambling establishments were known as saloons ...
... The breakup of Al-Andalus into the competing taifa kingdoms helped the long embattled Iberian Christian kingdoms gain the initiative ... The capture of the strategically central city of Toledo in 1085 marked a significant shift in the balance of power in favour of the Christian kingdoms ...
... The history of computing is longer than the history of computing hardware and modern computing technology and includes the history of methods intended for pen ...
Famous quotes containing the word history:
“The history of mens opposition to womens emancipation is more interesting perhaps than the story of that emancipation itself.”
—Virginia Woolf (18821941)
“Spain is an overflow of sombreness ... a strong and threatening tide of history meets you at the frontier.”
—Wyndham Lewis (18821957)
“America is the only nation in history which, miraculously, has gone directly from barbarism to degeneration without the usual interval of civilization.”
—Attributed to Georges Clemenceau (18411929)