World Wide Web Consortium

he World Wide Web Consortium (W3C) is the main international standards organization for the World Wide Web (abbreviated WWW or W3).


Founded and currently led by Tim Berners-Lee, the consortium is made up of member organizations which maintain full-time staff for the purpose of working together in the development of standards for the World Wide Web. As of 7 September 2013, the World Wide Web Consortium (W3C) has 383 members.

W3C also engages in education and outreach, develops software and serves as an open forum for discussion about the Web.

Uniform Type Identifier

                  A Uniform Type Identifier (UTI) is a text string used on software provided by Apple Inc. to uniquely identify a given class or type of item. Apple provides built-in UTIs to identify common system objects — document or image file types, folders and application bundles, streaming data, clipping data, movie data — and allows third party developers to add their own UTIs for application-specific or proprietary uses. Support for UTIs was added in the Mac OS X 10.4 operating system, integrated into the Spotlight desktop search technology, which uses UTIs to categorize documents. One of the primary design goals of UTIs was to eliminate the ambiguities and problems associated with inferring a file's content from its MIME type, filename extension, or type or creator code.

            UTIs use a reverse-DNS naming structure. Names may include the ASCII characters A-Z, a-z, 0-9, hyphen ("-"), and period ("."), and all Unicode characters above U+007F.[1] Colons and slashes are prohibited for compatibility with Macintosh and POSIX file path conventions. UTIs support multiple inheritance, allowing files to be identified with any number of relevant types, as appropriate to the contained data.

Standard Generalized Markup Language

              The Standard Generalized Markup Language (SGML; ISO 8879:1986) is an ISO-standard technology for defining generalized markup languages for documents. ISO 8879 Annex A.1 defines generalized markup:

    Generalized markup is based on two novel postulates.

     Markup should be declarative: it should describe a document's structure and other attributes, rather than specify the processing to be performed on it. Declarative markup is less likely to conflict with unforeseen future processing needs and techniques.

               Markup should be rigorous so that the techniques available for processing rigorously-defined objects like programs and databases can be used for processing documents as well.
HTML is an example of an SGML-based language.

Markup language

              (document) markup language is a modern system for annotating a document in a way that is syntactically distinguishable from the text. The idea and terminology evolved from the "marking up" of paper manuscripts, i.e., the revision instructions by editors, traditionally written with a blue pencil on authors' manuscripts. In digital media this "blue pencil instruction text" was replaced by tags, that is, instructions are expressed directly by tags or "instruction text encapsulated by tags".

            Examples are typesetting instructions such as those found in troff, TeX and LaTeX, or structural markers such as XML tags. Markup instructs the software displaying the text to carry out appropriate actions, but is omitted from the version of the text that is displayed to users. Some markup languages, such as HTML, have pre-defined presentation semantics, meaning that their specification prescribes how the structured data are to be presented; others, such as XML, do not.

                A widely used markup language is HyperText Markup Language (HTML), one of the document formats of the World Wide Web. HTML, which is an instance of SGML (though, strictly, it does not comply with all the rules of SGML), follows many of the markup conventions used in the publishing industry in the communication of printed work between authors, editors, and printers.

HTML

HTML or HyperText Markup Language is the main markup language for creating web pages and other information that can be displayed in a web browser.

           HTML is written in the form of HTML elements consisting of tags enclosed in angle brackets (like <html>), within the web page content. HTML tags most commonly come in pairs like <h1> and </h1>, although some tags represent empty elements and so are unpaired, for example <img>. The first tag in a pair is the start tag, and the second tag is the end tag (they are also called opening tags and closing tags). In between these tags web designers can add text, further tags, comments and other types of text-based content.

           The purpose of a web browser is to read HTML documents and compose them into visible or audible web pages. The browser does not display the HTML tags, but uses the tags to interpret the content of the page.
HTML elements form the building blocks of all websites. HTML allows images and objects to be embedded and can be used to create interactive forms. It provides a means to create structured documents by denoting structural semantics for text such as headings, paragraphs, lists, links, quotes and other items. It can embed scripts written in languages such as JavaScript which affect the behavior of HTML web pages.

          Web browsers can also refer to Cascading Style Sheets (CSS) to define the appearance and layout of text and other material. The W3C, maintainer of both the HTML and the CSS standards, encourages the use of CSS over explicit presentational HTML.[1]