A markup language is a text-encoding system which specifies the structure and formatting of a document and potentially the relationships among its parts. Markup can control the display of a document or enrich its content to facilitate automated processing.
90-425: Hypertext Markup Language ( HTML ) is the standard markup language for documents designed to be displayed in a web browser . It defines the content and structure of web content . It is often assisted by technologies such as Cascading Style Sheets (CSS) and scripting languages such as JavaScript, a programming language. Web browsers receive HTML documents from a web server or from local storage and render
180-510: A Document type declaration (informally, a "doctype"). In browsers, the doctype helps to define the rendering mode—particularly whether to use quirks mode . The original purpose of the doctype was to enable the parsing and validation of HTML documents by SGML tools based on the Document type definition (DTD). The DTD to which the DOCTYPE refers contains a machine-readable grammar specifying
270-404: A grammar that controlled the usage of descriptive elements. Scribe influenced the development of Generalized Markup Language (later SGML), and is a direct ancestor to HTML and LaTeX . In the early 1980s, the idea that markup should focus on the structural aspects of a document and leave the visual presentation of that structure to the interpreter led to the creation of SGML . The language
360-514: A schema ). This allowed authors to create and use any markup they wished, selecting tags that made the most sense to them and were named in their own natural languages, while also allowing automated verification. Thus, SGML is properly a meta-language , and many particular markup languages are derived from it. From the late '80s onward, most substantial new markup languages have been based on the SGML system, including for example TEI and DocBook . SGML
450-406: A contractor at CERN , proposed and prototyped ENQUIRE , a system for CERN researchers to use and share documents. In 1989, Berners-Lee wrote a memo proposing an Internet -based hypertext system. Berners-Lee specified HTML and wrote the browser and server software in late 1990. That year, Berners-Lee and CERN data systems engineer Robert Cailliau collaborated on a joint request for funding, but
540-417: A descriptive markup system on top of TeX, and is widely used both among the scientific community and the publishing industry. The first language to make a clean distinction between structure and presentation was Scribe , developed by Brian Reid and described in his doctoral thesis in 1980. Scribe was revolutionary in a number of ways, introducing the idea of styles separated from the marked-up document, and
630-422: A key goal, and without input from standards organizations, aimed at allowing authors to create formatted text via web browsers , for example in wikis and in web forums . These are sometimes called lightweight markup languages . Markdown , BBCode , and the markup language used by Misplaced Pages are examples of such languages. The first well-known public presentation of markup languages in computer text processing
720-476: A markup-language-based format. Another major publishing standard is TeX , created and refined by Donald Knuth in the 1970s and '80s. TeX concentrated on the detailed layout of text and font descriptions to typeset mathematical books. This required Knuth to spend considerable time investigating the art of typesetting . TeX is mainly used in academia , where it is a de facto standard in many scientific disciplines. A TeX macro package known as LaTeX provides
810-584: A memo proposing an Internet -based hypertext system, then specified HTML and wrote the browser and server software in the last part of 1990. The first publicly available description of HTML was a document called "HTML Tags", first mentioned on the Internet by Berners-Lee in late 1991. It describes 18 elements comprising the initial, relatively simple design of HTML. Except for the hyperlink tag, these were strongly influenced by SGMLguid , an in-house SGML -based documentation format at CERN , and very similar to
900-594: A modified IBM 7090 mainframe computer that had two 32,768 (32K) 36-bit- word banks of core memory instead of the default configuration which provides only one. One bank was reserved for the time-sharing supervisory program, the other for user programs. CTSS had a protected-mode kernel; the supervisor's functions in the A-core (memory bank A) could be called only by software interrupts, as in modern operating systems. Causing memory-protection interrupts were used for software interrupts. Processor allocation scheduling with
990-451: A pair is the start tag , and the second is the end tag (they are also called opening tags and closing tags ). Another important component is the HTML document type declaration , which triggers standards mode rendering. The following is an example of the classic "Hello, World!" program : The text between < html > and </ html > describes the web page, and
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#17327647772321080-604: A paper about that system at the Spring Joint Computer Conference . Robert C. Daley, Peter R. Bos and at least 6 other programmers implemented the operating system, partly based on the Fortran Monitor System . The system used an IBM 7090 , modified by Herbert M. Teager , with added 3 Flexowriters for user consoles, and maybe a timer . Each of the 3 users had two tape units , one for the user's file directory, and one for dumping
1170-434: A proper name, defined term, or another special item, the markup may be inserted between the characters of the sentence. The noun markup is derived from the traditional publishing practice called "marking up" a manuscript , which involves adding handwritten annotations in the form of conventional symbolic printer 's instructions — in the margins and the text of a paper or a printed manuscript. For centuries, this task
1260-516: A quantum time unit 200 ms, was controlled by a multilevel feedback queue . It also had some special memory-management hardware, a clock interrupt, and the ability to trap certain instructions. CTSS at first had only an assembler, FAP , and a compiler, MAD. Also, Fortran II code could be translated into MAD code by using MADTRN. Later half of the system was written in MAD. Later there were other programming languages including COMIT II , LISP 1.5 and
1350-760: A separate IBM 7094 that was received in October 1963 (the "red machine") was used early on in Project MAC until 1969 when the red machine was moved to the Information Processing Center and operated until July 20, 1973. CTSS ran on only those two machines; however, there were remote CTSS users outside of MIT including ones in California, South America, the University of Edinburgh and the University of Oxford . John Backus said in
1440-425: A start tag) and do not use an end tag. Many tags, particularly the closing end tag for the very commonly used paragraph element < p > , are optional. An HTML browser or other agent can infer the closure for the end of an element from the context and the structural rules defined by the HTML standard. These rules are complex and not widely understood by most HTML authors. The general form of an HTML element
1530-414: A tag such as "h1" (header level 1) might be presented in a large bold sans-serif typeface in an article, or it might be underscored in a monospaced (typewriter-style) document – or it might simply not change the presentation at all. In contrast, the i tag in HTML 4 is an example of presentational markup, which is generally used to specify a particular characteristic of the text without specifying
1620-526: A taxonomic designation or a phrase in another language. The change was made to ease the transition from HTML 4 to HTML 5 as smoothly as possible so that deprecated uses of presentational elements would preserve the most likely intended semantics. The Text Encoding Initiative (TEI) has published extensive guidelines for how to encode texts of interest in the humanities and social sciences, developed through years of international cooperative work. These guidelines are used by projects encoding historical documents,
1710-594: A user can give input/s like: Comments: Comments can help in the understanding of the markup and do not display in the webpage. There are several types of markup elements used in HTML: Most of the attributes of an element are name–value pairs , separated by = and written within the start tag of an element after the element's name. The value may be enclosed in single or double quotes, although values consisting of certain characters can be left unquoted in HTML (but not XHTML). Leaving attribute values unquoted
1800-409: A version of ALGOL . Each user had their own directory , and there were also shared directories for groups of people with the same "problem number". Each file had two names, the second indicating its type as did the extension in later system. At first, each file could have one of four modes: temporary, permanent, read-only class 1, and read-only class 2. Read-only class 1 allowed the user to change
1890-404: A way that it is also an SGML document, and existing SGML users and software could switch to XML fairly easily. However, XML eliminated many of the more complex features of SGML to simplify implementation environments such as documents and publications. It appeared to strike a happy medium between simplicity and flexibility, as well as supporting very robust schema definition and validation tools, and
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#17327647772321980-497: Is a considerable blurring of the lines between the types of markup. In modern word-processing systems, presentational markup is often saved in descriptive-markup-oriented systems such as XML , and then processed procedurally by implementations . The programming in procedural-markup systems, such as TeX , may be used to create higher-level markup systems that are more descriptive in nature, such as LaTeX . In recent years, several markup languages have been developed with ease of use as
2070-461: Is considered unsafe. In contrast with name-value pair attributes, there are some attributes that affect the element simply by their presence in the start tag of the element, like the ismap attribute for the img element. There are several common attributes that may appear in many elements : The abbreviation element, abbr , can be used to demonstrate some of these attributes: This example displays as HTML ; in most browsers, pointing
2160-453: Is for HTML5. If a declaration is not included, various browsers will revert to " quirks mode " for rendering. HTML documents imply a structure of nested HTML elements . These are indicated in the document by HTML tags , enclosed in angle brackets thus: < p > . In the simple, general case, the extent of an element is indicated by a pair of tags: a "start tag" < p > and "end tag" </ p > . The text content of
2250-637: Is more commonly seen today as the "father" of markup languages. Goldfarb hit upon the basic idea while working on a primitive document management system intended for law firms in 1969, and helped invent IBM GML later that same year. GML was first publicly disclosed in 1973. In 1975, Goldfarb moved from Cambridge, Massachusetts to Silicon Valley and became a product planner at the IBM Almaden Research Center . There, he convinced IBM's executives to deploy GML commercially in 1978 as part of IBM's Document Composition Facility product, and it
2340-614: Is that all attribute values in tags must be quoted. Both these differences are commonly criticized as verbose but also praised because they make it far easier to detect, localize, and repair errors. Finally, all tag and attribute names within the XHTML namespace must be lowercase to be valid. HTML, on the other hand, was case-insensitive. Many XML-based applications now exist, including the Resource Description Framework as RDF/XML , XForms , DocBook , SOAP , and
2430-401: Is therefore: < tag attribute1 = "value1" attribute2 = "value2" > ''content'' </ tag > . Some HTML elements are defined as empty elements and take the form < tag attribute1 = "value1" attribute2 = "value2" > . Empty elements may enclose no content, for instance, the < br /> tag or
2520-558: Is typical for the internal representations that programs use to work with marked-up documents. However, embedded or "inline" markup is much more common elsewhere. Here, for example, is a small section of text marked up in HTML: The codes enclosed in angle-brackets <like this> are markup instructions (known as tags), while the text between these instructions is the actual text of the document. The codes h1 , p , and em are examples of semantic markup, in that they describe
2610-660: The American Printing House for the Blind to print the first braille edition of a book produced from teletypesetter input, only a few weeks after the ink-print version. The following year, on CTSS, a demonstration of printing mathematical tables in braille was shown. A short FORTRAN II program was written to produce a conversion table from inches to millimeters in braille via the BRAILLEMBOSS braille page printer. The Intrex Retrieval System ran on CTSS. Intrex
2700-496: The International Organization for Standardization committee that created SGML , the first standard descriptive markup language. Book designer Stanley Rice published speculation along similar lines in 1970. Brian Reid , in his 1980 dissertation at Carnegie Mellon University , developed the theory and a working implementation of descriptive markup in actual use. However, IBM researcher Charles Goldfarb
2790-587: The Internet Engineering Task Force (IETF) with the mid-1993 publication of the first proposal for an HTML specification, the "Hypertext Markup Language (HTML)" Internet Draft by Berners-Lee and Dan Connolly , which included an SGML Document type definition to define the syntax. The draft expired after six months, but was notable for its acknowledgment of the NCSA Mosaic browser's custom tag for embedding in-line images, reflecting
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2880-486: The Web Ontology Language (OWL). For a partial list of these, see List of XML markup languages . A common feature of many markup languages is that they intermix the text of a document with markup instructions in the same data stream or file. This is not necessary; it is possible to isolate markup from text content, using pointers, offsets, IDs, or other methods to coordinate the two. Such "standoff markup"
2970-433: The de facto web standard for some time. HTML markup consists of several key components, including those called tags (and their attributes ), character-based data types , character references and entity references . HTML tags most commonly come in pairs like < h1 > and </ h1 > , although some represent empty elements and so are unpaired, for example < img > . The first tag in such
3060-423: The "marking up" of paper manuscripts (e.g., with revision instructions by editors), traditionally written with a red pen or blue pencil on authors' manuscripts. Older markup languages, which typically focus on typography and presentation, include Troff , TeX , and LaTeX . Scribe and most modern markup languages, such as XML , identify document components (for example headings, paragraphs, and tables), with
3150-438: The 1954 summer session at MIT that "By time sharing, a big computer could be used as several small ones; there would need to be a reading station for each user". Computers at that time, like IBM 704 , were not powerful enough to implement such system, but at the end of 1958, MIT's Computation Center nevertheless added a typewriter input to its 704 with the intent that a programmer or operator could "obtain additional answers from
3240-497: The DTD in order to properly parse the document and to perform validation. In modern browsers, a valid doctype activates standards mode as opposed to quirks mode . Markup language A markup language is a set of rules governing what markup information may be included in a document and how it is combined with the content of the document in a way to facilitate use by humans and computer programs. The idea and terminology evolved from
3330-455: The IETF's philosophy of basing standards on successful prototypes. Similarly, Dave Raggett 's competing Internet Draft, "HTML+ (Hypertext Markup Format)", from late 1993, suggested standardizing already-implemented features like tables and fill-out forms. After the HTML and HTML+ drafts expired in early 1994, the IETF created an HTML Working Group. In 1995, this working group completed "HTML 2.0",
3420-590: The XML syntax for HTML and is no longer being developed as a separate standard. On 28 May 2019, the W3C announced that WHATWG would be the sole publisher of the HTML and DOM standards. The W3C and WHATWG had been publishing competing standards since 2012. While the W3C standard was identical to the WHATWG in 2007 the standards have since progressively diverged due to different design decisions. The WHATWG "Living Standard" had been
3510-473: The attribute value itself. If document authors overlook the need to escape such characters, some browsers can be very forgiving and try to use context to guess their intent. The result is still invalid markup, which makes the document less accessible to other browsers and to other user agents that may try to parse the document for search and indexing purposes for example. Escaping also allows for characters that are not easily typed, or that are not available in
3600-574: The browser, and these characteristics can be altered or enhanced by the web page designer's additional use of CSS . Many of the text elements are mentioned in the 1988 ISO technical report TR 9537 Techniques for using SGML , which describes the features of early text formatting languages such as that used by the RUNOFF command developed in the early 1960s for the CTSS (Compatible Time-Sharing System) operating system. These formatting commands were derived from
3690-433: The characters < and & (when written as < and & , respectively) to be interpreted as character data, rather than markup. For example, a literal < normally indicates the start of a tag, and & normally indicates the start of a character entity reference or numeric character reference; writing it as & or & or & allows & to be included in
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3780-440: The characters of the world's writing systems. HTML defines several data types for element content, such as script data and stylesheet data, and a plethora of types for attribute values, including IDs, names, URIs , numbers, units of length, languages, media descriptors, colors, character encodings, dates and times, and so on. All of these data types are specializations of character data. HTML documents are required to start with
3870-400: The commands used by typesetters to manually format documents. However, the SGML concept of generalized markup is based on elements (nested annotated ranges with attributes) rather than merely print effects, with separate structure and markup. HTML has been progressively moved in this direction with CSS. Berners-Lee considered HTML to be an application of SGML. It was formally defined as such by
3960-537: The content of an element or in the value of an attribute. The double-quote character ( " ), when not used to quote an attribute value, must also be escaped as " or " or " when it appears within the attribute value itself. Equivalently, the single-quote character ( ' ), when not used to quote an attribute value, must also be escaped as ' or ' (or as ' in HTML5 or XHTML documents) when it appears within
4050-406: The core (program in memory). There was also one tape unit for the system commands, there were no disk drives. The memory was 27 k words (36-bit words) for users, and 5 k words for the supervisor (operating system). The input from the consoles was written to the buffers in the supervisor, by interrupts , and when a return character was received, the control was given to the supervisor, which dumped
4140-663: The cursor at the abbreviation should display the title text "Hypertext Markup Language." Most elements take the language-related attribute dir to specify text direction, such as with "rtl" for right-to-left text in, for example, Arabic , Persian or Hebrew . As of version 4.0, HTML defines a set of 252 character entity references and a set of 1,114,050 numeric character references , both of which allow individual characters to be written via simple markup, rather than literally. A literal character and its markup counterpart are considered equivalent and are rendered identically. The ability to " escape " characters in this way allows for
4230-570: The design of the Titan Supervisor was inspired by that. Dennis Ritchie wrote in 1977 that UNIX could be seen as a "modern implementation" of CTSS. Multics, which was also developed by Project MAC, was started in the 1960s as a successor to CTSS – and in turn inspired the development of Unix in 1969. One of the technical terms inherited by these systems from CTSS is daemon . Incompatible Timesharing System (ITS), another early, revolutionary, and influential MIT time-sharing system,
4320-476: The document text so that typesetting software could format the text according to the editor's specifications. It was a trial and error iterative process to get a document printed correctly. Availability of WYSIWYG ("what you see is what you get") publishing software supplanted much use of these languages among casual users, though serious publishing work still uses markup to specify the non-visual structure of texts, and WYSIWYG editors now usually save documents in
4410-589: The document's character encoding , to be represented within the element and attribute content. For example, the acute-accented e ( é ), a character typically found only on Western European and South American keyboards, can be written in any HTML document as the entity reference é or as the numeric references é or é , using characters that are available on all keyboards and are supported in all character encodings. Unicode character encodings such as UTF-8 are compatible with all modern browsers and allow direct access to almost all
4500-658: The documents into multimedia web pages. HTML describes the structure of a web page semantically and originally included cues for its appearance. HTML elements are the building blocks of HTML pages. With HTML constructs, images and other objects such as interactive forms may be embedded into the rendered page. HTML provides a means to create structured documents by denoting structural semantics for text such as headings, paragraphs, lists, links , quotes, and other items. HTML elements are delineated by tags , written using angle brackets . Tags such as < img > and < input > directly introduce content into
4590-445: The element, if any, is placed between these tags. Tags may also enclose further tag markup between the start and end, including a mixture of tags and text. This indicates further (nested) elements, as children of the parent element. The start tag may also include the element's attributes within the tag. These indicate other information, such as identifiers for sections within the document, identifiers used to bind style information to
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#17327647772324680-401: The expectation that technology, such as stylesheets , will be used to apply formatting or other processing. Some markup languages, such as the widely used HTML , have pre-defined presentation semantics , meaning that their specifications prescribe some aspects of how to present the structured data on particular media. HTML, like DocBook , Open eBook , JATS , and many others, is based on
4770-514: The first HTML specification intended to be treated as a standard against which future implementations should be based. Further development under the auspices of the IETF was stalled by competing interests. Since 1996, the HTML specifications have been maintained, with input from commercial software vendors, by the World Wide Web Consortium (W3C). In 2000, HTML became an international standard ( ISO / IEC 15445:2000). HTML 4.01
4860-497: The grammar. Many of the HTML text elements are found in the 1988 ISO technical report TR 9537 Techniques for using SGML , which in turn covers the features of early text formatting languages such as that used by the RUNOFF command developed in the early 1960s for the CTSS (Compatible Time-Sharing System) operating system. These formatting commands were derived from those used by typesetters to manually format documents. Steven DeRose argues that HTML's use of descriptive markup (and
4950-412: The head, for example: HTML headings are defined with the < h1 > to < h6 > tags with H1 being the highest (or most important) level and H6 the least: The effects are: CSS can substantially change the rendering. Paragraphs: < br /> . The difference between < br /> and < p > is that < br /> breaks a line without altering
5040-424: The hyperlink tag, these were strongly influenced by SGMLguid , an in-house Standard Generalized Markup Language (SGML)-based documentation format at CERN. Eleven of these elements still exist in HTML 4. HTML is a markup language that web browsers use to interpret and compose text, images, and other material into visible or audible web pages. Default characteristics for every item of HTML markup are defined in
5130-469: The influence of SGML in particular) was a major factor in the success of the Web, because of the flexibility and extensibility that it enabled. HTML became the main markup language for creating web pages and other information that can be displayed in a web browser and is likely the most used markup language in the world today. XML (Extensible Markup Language) is a meta markup language that is very widely used. XML
5220-402: The inline < img > tag. The name of an HTML element is the name used in the tags. The end tag's name is preceded by a slash character, / , and that in empty elements the end tag is neither required nor allowed. If attributes are not mentioned, default values are used in each case. Header of the HTML document: < head > ... </ head > . The title is included in
5310-446: The intended purpose or the meaning of the text they include. Specifically, h1 means "this is a first-level heading", p means "this is a paragraph", and em means "this is an emphasized word or phrase". A program interpreting such structural markup may apply its own rules or styles for presenting the various pieces of text, using different typefaces, boldness, font size, indentation, color, or other styles, as desired. For example,
5400-463: The look and layout of content. The World Wide Web Consortium (W3C), former maintainer of the HTML and current maintainer of the CSS standards, has encouraged the use of CSS over explicit presentational HTML since 1997. A form of HTML, known as HTML5 , is used to display video and audio, primarily using the < canvas > element, together with JavaScript. In 1980, physicist Tim Berners-Lee ,
5490-636: The machine on a time-sharing basis with other programs using the machine simultaneously". In June 1959, Christopher Strachey published a paper "Time Sharing in Large Fast Computers" at the UNESCO Information Processing Conference in Paris, where he envisaged a programmer debugging a program at a console (like a teletype ) connected to the computer, while another program was running in the computer at
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#17327647772325580-425: The markup meta-languages SGML and XML . That is, SGML and XML allow designers to specify particular schemas , which determine which elements, attributes, and other features are permitted, and where. A key characteristic of most markup languages is that they allow intermingling markup with document content such as text and pictures. For example, if a few words in a sentence need to be emphasized, or identified as
5670-424: The mode of the file. Files could also be symbolically linked between directories. A directory listing by listf : Input-output hardware was mostly standard IBM peripherals . These included six data channels connecting to: CTSS was described in a paper presented at the 1962 Spring Joint Computer Conference , and greatly influenced the design of other early time-sharing systems. Maurice Wilkes witnessed CTSS and
5760-415: The most noticeable differences between HTML and XHTML is the rule that all tags must be closed : empty HTML tags such as <br> must either be closed with a regular end-tag, or replaced by a special form: <br /> (the space before the ' / ' on the end tag is optional, but frequently used because it enables some pre-XML Web browsers, and SGML parsers, to accept the tag). Another difference
5850-413: The page. Other tags such as < p > and </ p > surround and provide information about document text and may include sub-element tags. Browsers do not display the HTML tags but use them to interpret the content of the page. HTML can embed programs written in a scripting language such as JavaScript , which affects the behavior and content of web pages. The inclusion of CSS defines
5940-433: The permitted and prohibited content for a document conforming to such a DTD. Browsers, on the other hand, do not implement HTML as an application of SGML and as consequence do not read the DTD. HTML5 does not define a DTD; therefore, in HTML5 the doctype declaration is simpler and shorter: An example of an HTML 4 doctype This declaration references the DTD for the "strict" version of HTML 4.01. SGML-based validators read
6030-445: The possibility of combining multiple markup languages into a single profile, like XHTML+SMIL and XHTML+MathML+SVG . Compatible Time-Sharing System The Compatible Time-Sharing System ( CTSS ) was the first general purpose time-sharing operating system . Compatible Time Sharing referred to time sharing which was compatible with batch processing ; it could offer both time sharing and batch processing concurrently. CTSS
6120-412: The presentation of the document, and for some tags such as the < img > used to embed images, the reference to the image resource in the format like this: < img src = "example.com/example.jpg" > Some elements, such as the line break < br /> do not permit any embedded content, either text or further tags. These require only a single empty tag (akin to
6210-431: The project was not formally adopted by CERN. In his personal notes of 1990, Berners-Lee listed "some of the many areas in which hypertext is used"; an encyclopedia is the first entry. The first publicly available description of HTML was a document called "HTML Tags", first mentioned on the Internet by Tim Berners-Lee in late 1991. It describes 18 elements comprising the initial, relatively simple design of HTML. Except for
6300-458: The reason for that appearance. In this case, the i element dictates the use of an italic typeface. However, in HTML 5 , this element has been repurposed with a more semantic usage: to denote a span of text in an alternate voice or mood, or otherwise offset from the normal prose in a manner indicating a different quality of text . For example, it is appropriate to use the i element to indicate
6390-582: The running code to the tape and decided what to run next. The console commands implemented at the time were login, logout, input, edit, fap, mad, madtrn, load, use, start, skippm, listf, printf, xdump and xundump . This became the initial version of the Compatible Time-Sharing System. This was apparently the first ever public demonstration of time-sharing ; there are other claims, but they refer to special-purpose systems, or with no known papers published. The "compatibility" of CTSS
6480-621: The same time, decided the details of implementing such system at MIT, and started the development of the system. By July, 1961 a few time sharing commands had become operational on the Computation Center's IBM 709, and in November 1961, Fernando J. Corbató demonstrated at MIT what was called the Experimental Time-Sharing System . On May 3, 1962, F. J. Corbató, M. M. Daggett and R. C. Daley published
6570-408: The same time. Debugging programs was an important problem at that time, because with batch processing, it then often took a day from submitting a changed code, to getting the results. John McCarthy wrote a memo about that at MIT, after which a preliminary study committee and a working committee were established at MIT, to develop time sharing. The committees envisaged many users using the computer at
6660-549: The sample schema in the SGML standard. Eleven of these elements still exist in HTML 4. Berners-Lee considered HTML an SGML application. The Internet Engineering Task Force (IETF) formally defined it as such with the mid-1993 publication of the first proposal for an HTML specification: "Hypertext Markup Language (HTML)" Internet-Draft Archived 2017-01-03 at the Wayback Machine by Berners-Lee and Dan Connolly , which included an SGML Document Type Definition to define
6750-471: The semantic structure of the page, whereas < p > sections the page into paragraphs . The element < br /> is an empty element in that, although it may have attributes, it can take no content and it may not have an end tag. This is a link in HTML. To create a link the < a > tag is used. The href attribute holds the URL address of the link. There are many possible ways
6840-517: The text between < body > and </ body > is the visible page content. The markup text < title > This is a title </ title > defines the browser page title shown on browser tabs and window titles and the tag < div > defines a division of the page used for easy styling. Between < head > and </ head > , a < meta > element can be used to define webpage metadata. The Document Type Declaration <!DOCTYPE html>
6930-452: The works of particular scholars, periods, genres, and so on. While the idea of markup language originated with text documents, there is increasing use of markup languages in the presentation of other types of information, including playlists , vector graphics , web services , content syndication , and user interfaces . Most of these are XML applications because XML is a well-defined and extensible language. The use of XML has also led to
7020-478: Was an experimental, pilot-model machine-oriented bibliographic storage and retrieval system with a database that stored a catalog of roughly 15,000 journal articles. It was used to develop and test concepts for library automation. A deployment of three BRISC CRT consoles for testing at the MIT Engineering Library showed that it was preferred over two other systems, ARDS and DATEL. CTSS used
7110-404: Was converted to Grade 2 Braille. The following month the feasibility of converting textbook information on teletypesetter tape to error-free Grade 2 Braille was successfully demonstrated. As MIT CTSS was an academic system, a research vehicle and not a system for commercial computing, two years later a version of DOTSYS stripped of CTSS dependencies for software portability was used on an IBM 709 at
7200-592: Was developed at the MIT Computation Center ("Comp Center"). CTSS was first demonstrated on MIT's modified IBM 709 in November 1961. The hardware was replaced with a modified IBM 7090 in 1962 and later a modified IBM 7094 called the "blue machine" to distinguish it from the Project MAC CTSS IBM 7094. Routine service to MIT Comp Center users began in the summer of 1963 and was operated there until 1968. A second deployment of CTSS on
7290-512: Was developed by a committee chaired by Goldfarb. It incorporated ideas from many different sources, including Tunnicliffe's project, GenCode. Sharon Adler, Anders Berglund, and James A. Marke were also key members of the SGML committee. SGML specified a syntax for including the markup in documents, as well as one for separately describing what tags were allowed, and where (the Document Type Definition ( DTD ), later known as
7380-444: Was developed by the World Wide Web Consortium in a committee created and chaired by Jon Bosak . The main purpose of XML was to simplify SGML by focusing on a particular problem — documents on the Internet. XML remains a meta-language like SGML, allowing users to create any tags needed (hence "extensible") and then describing those tags and their permitted uses. XML adoption was helped because every XML document can be written in such
7470-664: Was done primarily by skilled typographers known as "markup men" or "markers" who marked up text to indicate what typeface , style, and size should be applied to each part, and then passed the manuscript to others for typesetting by hand or machine. The markup was also commonly applied by editors, proofreaders , publishers, and graphic designers, and indeed by document authors, all of whom might also mark other things, such as corrections, changes, etc. There are three main general categories of electronic markup, articulated in Coombs, Renear, and DeRose (1987), and Bray (2003). There
7560-419: Was made by William W. Tunnicliffe at a conference in 1967, although he preferred to call it generic coding. It can be seen as a response to the emergence of programs such as RUNOFF that each used their own control notations, often specific to the target typesetting device. In the 1970s, Tunnicliffe led the development of a standard called GenCode for the publishing industry and later was the first chairman of
7650-455: Was produced by people who disagreed with the direction taken by CTSS, and later, Multics; the name was a parody of "CTSS", as later the name "Unix" was a parody of "Multics". CTSS and ITS file systems have a number of design elements in common. Both have an M.F.D. (master file directory) and one or more U.F.D. (user file directories). Neither of them have nested directories (sub-directories). Both have file names consisting of two names which are
7740-631: Was promulgated as an International Standard by International Organization for Standardization , ISO 8879, in 1986. SGML found wide acceptance and use in fields with very large-scale documentation requirements. However, many found it cumbersome and difficult to learn — a side effect of its design attempting to do too much and being too flexible. For example, SGML made end tags (or start-tags, or even both) optional in certain contexts, because its developers thought markup would be done manually by overworked support staff who would appreciate saving keystrokes . In 1989, computer scientist Sir Tim Berners-Lee wrote
7830-514: Was published in late 1999, with further errata published through 2001. In 2004, development began on HTML5 in the Web Hypertext Application Technology Working Group (WHATWG), which became a joint deliverable with the W3C in 2008, and was completed and standardized on 28 October 2014. XHTML is a separate language that began as a reformulation of HTML 4.01 using XML 1.0. It is now referred to as
7920-735: Was rapidly adopted for many other uses. XML is now widely used for communicating data between applications, for serializing program data, for hardware communications protocols, vector graphics, and many other uses as well as documents. From January 2000 until HTML 5 was released, all W3C Recommendations for HTML have been based on XML, using the abbreviation XHTML ( Ex tensible H yper T ext M arkup L anguage). The language specification requires that XHTML Web documents be well-formed XML documents. This allows for more rigorous and robust documents, by avoiding many syntax errors which historically led to incompatible browser behaviors, while still using document components that are familiar with HTML. One of
8010-568: Was widely used in business within a few years. SGML, which was based on both GML and GenCode, was an ISO project worked on by Goldfarb beginning in 1974. Goldfarb eventually became chair of the SGML committee. SGML was first released by ISO as the ISO 8879 standard in October 1986. Some early examples of computer markup languages available outside the publishing industry can be found in typesetting tools on Unix systems such as troff and nroff . In these systems, formatting commands were inserted into
8100-461: Was with background jobs run on the same computer, which generally used more of the compute resources than the time-sharing functions. The first version of the DOTSYS braille translation software ran on CTSS and could output to a BRAILLEMBOSS braille page printer. DOTSYS on CTSS was first demonstrated on August 18, 1966, as part of a feasibility study where teletypesetter tape, in the form of news,
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