57-476: The Web Hypertext Application Technology Working Group ( WHATWG ) is a community of people interested in evolving HTML and related technologies. The WHATWG was founded by individuals from Apple Inc. , the Mozilla Foundation and Opera Software , leading Web browser vendors in 2004. WHATWG is responsible for maintaining multiple web-related technical standards , including the specifications for
114-510: 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
171-486: 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 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
228-407: 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
285-454: A few years, Microsoft gained a dominant position in the browser market for two reasons: it bundled Internet Explorer with its popular Windows operating system and did so as freeware with no restrictions on usage. The market share of Internet Explorer peaked at over 95% in the early 2000s. In 1998, Netscape launched what would become the Mozilla Foundation to create a new browser using the open-source software model. This work evolved into
342-451: 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
399-457: A range of devices, including desktops , laptops , tablets , and smartphones . By 2020, an estimated 4.9 billion people had used a browser. The most-used browser is Google Chrome , with a 67% global market share on all devices, followed by Safari with 18%. A web browser is not the same thing as a search engine , though the two are often confused. A search engine is a website that provides links to other websites. However, to connect to
456-425: 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
513-596: 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
570-408: A website's server and display its web pages, a user must have a web browser installed. In some technical contexts, browsers are referred to as user agents . The purpose of a web browser is to fetch content and display it on the user's device. This process begins when the user inputs a Uniform Resource Locator (URL), such as https://en.wikipedia.org/ , into the browser. Virtually all URLs on
627-464: 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
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#1732765030869684-456: 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
741-401: 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
798-452: The whattf.org and whatwg.org domain names , the name WHATWG was eventually standardized on. The namespace URI http://whattf.org/datatype-draft remains in use for the HTML validator's data type library . 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
855-558: The Firefox browser, first released by Mozilla in 2004. Firefox's market share peaked at 32% in 2010. Apple released its Safari browser in 2003; it remains the dominant browser on Apple devices, though it did not become popular elsewhere. Google debuted its Chrome browser in 2008, which steadily took market share from Internet Explorer and became the most popular browser in 2012. Chrome has remained dominant ever since. By 2015, Microsoft replaced Internet Explorer with Edge for
912-675: The HyperText Markup Language (HTML) and the Document Object Model (DOM). The central organizational membership and control of WHATWG – its "Steering Group" – consists of Apple, Mozilla, Google, and Microsoft. WHATWG community members work with the editor of the specifications to ensure correct implementation. The WHATWG was formed in response to the slow development of World Wide Web Consortium (W3C) Web standards and W3C's decision to abandon HTML in favor of XML -based technologies. The WHATWG mailing list
969-589: 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
1026-482: The Windows 10 release. Since the early 2000s, browsers have greatly expanded their HTML , CSS , JavaScript , and multimedia capabilities. One reason has been to enable more sophisticated websites, such as web apps . Another factor is the significant increase of broadband connectivity in many parts of the world, enabling people to access data-intensive content, such as streaming HD video on YouTube , that
1083-434: 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
1140-485: 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 . Web browser A web browser is an application for accessing websites . When a user requests a web page from a particular website, the browser retrieves its files from a web server and then displays the page on the user's screen. Browsers are used on
1197-456: 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",
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#17327650308691254-507: 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 the de facto web standard for some time. The WHATWG publishes a number of standards that form a substantial portion of the web platform including: HTML Hypertext Markup Language ( HTML ) is the standard markup language for documents designed to be displayed in
1311-421: The WHATWG established an intellectual property rights agreement that includes a patent policy. This spurred a renewed attempt to allow the W3C and the WHATWG to work together on specifications. In 2019, the W3C and WHATWG agreed to a memorandum of understanding where development of HTML and DOM specifications would be done principally in the WHATWG. The editor has significant control over the specification, but
1368-472: The WHATWG specification was later renamed HTML Living Standard ). On 9 May 2007, the new HTML working group of the W3C resolved to do that. An Internet Explorer platform architect from Microsoft was invited but did not join, citing the lack of a patent policy to ensure all specifications can be implemented on a royalty-free basis. Since then, the W3C and the WHATWG had been developing HTML independently, at times causing specifications to diverge. In 2017,
1425-542: The Web start with either http: or https: which means they are retrieved with the Hypertext Transfer Protocol (HTTP). For secure mode (HTTPS), the connection between the browser and web server is encrypted , providing a secure and private data transfer. Web pages usually contain hyperlinks to other pages and resources. Each link contains a URL, and when it is clicked or tapped ,
1482-494: 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
1539-473: 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
1596-611: The average person. This, in turn, sparked the Internet boom of the 1990s, when the Web grew at a very rapid rate. The lead developers of Mosaic then founded the Netscape corporation, which released the Mosaic-influenced Netscape Navigator in 1994. Navigator quickly became the most popular browser. Microsoft debuted Internet Explorer in 1995, leading to a browser war with Netscape. Within
1653-401: The browser navigates to the new resource. Most browsers use an internal cache of web page resources to improve loading times for subsequent visits to the same page. The cache can store many items, such as large images, so they do not need to be downloaded from the server again. Cached items are usually only stored for as long as the web server stipulates in its HTTP response messages. During
1710-574: 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
1767-486: 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
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1824-433: 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
1881-441: 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
1938-451: 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
1995-442: The community can influence the decisions of the editor. In one case, editor Ian Hickson proposed replacing the <time> tag with a more generic <data> tag, but the community disagreed and the change was reverted. Initially, the name Web Hypertext Application Technology Task Force was also used, along with variant abbreviations including WHAT Working Group , WHAT Task Force and WHATTF . After some time using both
2052-539: 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
2109-433: The course of browsing, cookies received from various websites are stored by the browser. Some of them contain login credentials or site preferences. However, others are used for tracking user behavior over long periods of time, so browsers typically provide a section in the menu for deleting cookies. Finer-grained management of cookies usually requires a browser extension . The first web browser, called WorldWideWeb ,
2166-664: 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
2223-589: 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
2280-445: 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
2337-517: 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
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2394-412: 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
2451-425: 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
2508-402: 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
2565-465: 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 ,
2622-413: 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
2679-434: 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
2736-412: 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
2793-435: 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
2850-471: 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
2907-517: 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>
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#17327650308692964-508: The top four are made from different codebases . Safari , based on Apple 's WebKit code, is the second most popular web browser and is dominant on Apple devices, resulting in an 18% global share. Firefox , in fourth place, with about 3% market share, is based on Mozilla 's code. Both of these codebases are open-source, so a number of small niche browsers are also made from them. The most popular browsers share many features in common. They automatically log users' browsing history , unless
3021-461: The users turn off their browsing history or use the non-logging private mode . They also allow users to set bookmarks , customize the browser with extensions , and can manage user passwords . Some provide a sync service and web accessibility features. Common user interface (UI) features: While mobile browsers have similar UI features as desktop versions, the limitations of touch screens require mobile UIs to be simpler. The difference
3078-567: Was announced on 4 June 2004, two days after the initiatives of a joint Opera–Mozilla position paper had been voted down by the W3C members at the W3C Workshop on Web Applications and Compound Documents. On 10 April 2007, the Mozilla Foundation, Apple, and Opera Software proposed that the new HTML working group of the W3C adopt the WHATWG's HTML5 as the starting point of its work and name its future deliverable as "HTML5" (though
3135-592: Was created in 1990 by Sir Tim Berners-Lee . He then recruited Nicola Pellow to write the Line Mode Browser , which displayed web pages on dumb terminals . The Mosaic web browser was released in April 1993, and was later credited as the first web browser to find mainstream popularity. Its innovative graphical user interface made the World Wide Web easy to navigate and thus more accessible to
3192-550: Was not possible during the era of dial-up modems . Google Chrome has been the dominant browser since the mid-2010s and currently has a 67% global market share on all devices. The vast majority of its source code comes from Google's open-source Chromium project; this code is also the basis for many other browsers, including Microsoft Edge , currently in third place with about a 5% share, as well as Samsung Internet and Opera in fifth and sixth places respectively with over 2% market share each. The other two browsers in
3249-515: 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
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