HTML: Difference between revisions

Revision as of 21:04, 22 June 2024

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{{HTML}}

'''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 [[CSS|Cascading Style Sheets]] (CSS) and [[scripting languagelanguages]]s such as [[JavaScript]].

[[Web browserbrowsers]]s receive HTML documents from a [[web server]] or from local storage and [[browser engine|render]] the documents into multimedia web pages. HTML describes the structure of a [[web page]] [[Semantic Web|semantically]] and originally included cues for its appearance.

[[HTML element]]s are the building blocks of HTML pages. With HTML constructs, [[HTML element#Images and objects|images]] and other objects such as [[Fieldset|interactive forms]] may be embedded into the rendered page. HTML provides a means to create [[structured document]]s by denoting structural [[semantics]] for text such as headings, paragraphs, lists, [[Hyperlink|links]], quotes, and other items. HTML elements are delineated by ''tags'', written using [[Bracket#Angle brackets|angle brackets]]. Tags such as {{code|lang=html|code=<img>}} and {{code|lang=html|<input>}} directly introduce content into the page. Other tags such as {{code|lang=html|code=<p>}} and {{code|lang=html|code=</p>}} surround and provide information about document text and may include sub-element tags. [[Web browser|Browsers]] do not display the HTML tags but use them to interpret the content of the page.

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The first publicly available description of HTML was a document called "HTML Tags",<ref>{{cite web |title=Tags used in HTML |url=http://info.cern.ch/hypertext/WWW/MarkUp/Tags.html |website=info.cern.ch |access-date=2 March 2023 |date=October 1991}}</ref> first mentioned on the Internet by Tim Berners-Lee in late 1991.<ref name="tagshtml" /><ref>{{cite web|title=Re: status. Re: X11 BROWSER for WWW |url=http://lists.w3.org/Archives/Public/www-talk/1991SepOct/0003.html|last=Berners-Lee|first=Tim|date=October 29, 1991|publisher=World Wide Web Consortium|url-status=live|archive-url=https://web.archive.org/web/20070524045009/http://lists.w3.org:80/Archives/Public/www-talk/1991SepOct/0003.html|archive-date=May 24, 2007|access-date=April 8, 2007}}</ref> 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 [[Standard Generalized Markup Language]] (SGML)-based documentation format at CERN. Eleven of these elements still exist in HTML 4.<ref>{{cite web|title=Index of the HTML 4 elements |url=https://www.w3.org/TR/1999/REC-html401-19991224/index/elements|date=December 24, 1999|publisher=World Wide Web Consortium|url-status=live|archive-url=https://web.archive.org/web/20070505172415/https://www.w3.org/TR/1999/REC-html401-19991224/index/elements|archive-date=May 5, 2007|access-date=April 8, 2007}}</ref>

HTML is a [[markup language]] that [[web browserbrowsers]]s use to interpret and [[Typesetting|compose]] text, images, and other material into visible or audible web pages. Default characteristics for every item of HTML markup are defined in 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 [[TYPSET and RUNOFF|RUNOFF command]] developed in the early 1960s for the [[Compatible Time-Sharing System|CTSS]] (Compatible Time-Sharing System) operating system. These formatting commands were derived from 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 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 (computer scientist)|Dan Connolly]], which included an SGML [[Document type definition]] to define the syntax.<ref>{{cite web|title=Re: SGML/HTML docs, X Browser |url=http://lists.w3.org/Archives/Public/www-talk/1991NovDec/0020.html|author=Berners-Lee|first=Tim|date=December 9, 1991|website=w3|url-status=live|archive-url=https://web.archive.org/web/20071222060359/http://lists.w3.org/Archives/Public/www-talk/1991NovDec/0020.html|archive-date=December 22, 2007|access-date=June 16, 2007|quote=SGML is very general. HTML is a specific application of the SGML basic syntax applied to hypertext documents with simple structure. }}</ref><ref>{{Cite web|title=Hypertext Markup Language (HTML): A Representation of Textual Information and MetaInformation for Retrieval and Interchange|url=https://www.w3.org/MarkUp/draft-ietf-iiir-html-01.txt|last1=Berners-Lee|first1=Tim|last2=Connolly|first2=Daniel|date=June 1993|website=w3|url-status=live|archive-url=https://web.archive.org/web/20170103041713/https://www.w3.org/MarkUp/draft-ietf-iiir-html-01.txt|archive-date=January 3, 2017|access-date=January 4, 2017}}</ref> The draft expired after six months, but was notable for its acknowledgment of the [[Mosaic (web browser)|NCSA Mosaic]] browser's custom tag for embedding in-line images, reflecting 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.<ref name="html+">{{cite web|title=A Review of the HTML+ Document Format |url=http://www.w3.org/MarkUp/htmlplus_paper/htmlplus.html|author=Raggett, Dave|author-link=Dave Raggett|website=w3|url-status=live |archive-url=https://web.archive.org/web/20000229205146/http://www.w3.org/MarkUp/htmlplus_paper/htmlplus.html|archive-date=February 29, 2000|access-date=May 22, 2020|quote=The hypertext markup language HTML was developed as a simple non-proprietary delivery format for global hypertext. HTML+ is a set of modular extensions to HTML and has been developed in response to a growing understanding of the needs of information providers. These extensions include text flow around floating figures, fill-out forms, tables, and mathematical equations.}}</ref>