HTML 5 -Representing World Wide Web Consortium

HTML 5 -Representing World Wide Web Consortium :

HTML 5 is a core technology markup language of the Internet used for structuring and presenting content for the World Wide Web. As of October 2014 this is the final and complete fifth revision of the HTML standard of the World Wide Web Consortium (W3C).The previous version, HTML 4, was standardized in 1997.

Its core aims have been to improve the language with support for the latest multimedia while keeping it easily readable by humans and consistently understood by computers and devices (web browsers, parsers, etc.). HTML5 is intended to subsume not onlyHTML 4, but also XHTML 1 and DOM Level 2 HTML.

Following its immediate predecessors HTML 4.01 and XHTML 1.1, HTML5 is a response to the fact that the HTML and XHTML in common use on the World Wide Web are a mixture of features introduced by various specifications, along with those introduced by software products such as web browsers, those established by common practice. It is also an attempt to define a single markup language that can be written in either HTML or XHTML. It includes detailed processing models to encourage more interoperable implementations; it extends, improves and rationalizes the markup available for documents, and introduces markup and application programming interfaces (APIs) for complex web applications.

In particular, HTML5 adds many new syntactic features. These include the new <video>, <audio> and <canvas> elements, as well as the integration of scalable vector graphics (SVG) content (replacing generic <object> tags), and MathML for mathematical formulas. These features are designed to make it easy to include and handle multimedia and graphical content on the web without having to resort to proprietary plugins and APIs. Other new page structure elements, such as <main>, <section>, <article>,<header>, <footer>, <aside>, <nav> and <figure>, are designed to enrich the semantic content of documents. Newattributes have been introduced.

Standardization process :

The Mozilla Foundation and Opera Software presented a position paper at a World Wide Web Consortium (W3C) workshop in June 2004, focusing on developing technologies that are backward compatible with existing browsers, including an initial draft specification of Web Forms 2.0. The workshop concluded with a vote, 8 for, 14 against, for continuing work on HTML. Immediately after the workshop, 

Features and APIs

• HTML Working Group – HTML Canvas 2D Context

• Web Apps WG – Web Messaging, Web Workers, Web Storage, WebSocket API, Server-Sent Events

• IETF HyBi WG – WebSocket Protocol

• WebRTC WG – WebRTC

• W3C Web Media Text Tracks CG – WebVTT

HTML5 related APIs.

• The canvas element for immediate mode 2D drawing. See Canvas 2D API Specification 1.0 specification

• Timed media playback

• Offline Web Applications

• Document editing

• Drag-and-drop

• Cross-document messaging

• Browser history management

• MIME type and protocol handler registration

• Microdata

• Web Storage, a key-value pair storage framework that provides behaviour similar to cookies but with larger storage capacity and improved API.

• Geolocation

• Web SQL Database, a local SQL Database (no longer maintained).

• The Indexed Database API, an indexed hierarchical key-value store (formerly WebSimpleDB).

• HTML5 File API, handles file uploads and file manipulation.

• Directories and System, an API intended to satisfy client-side-storage use cases not well served by databases.

• File Writer, an API for writing to files from web applications.

• Web Audio API, a high-level JavaScript API for processing and synthesizing audio in web applications.

• ClassList API.

XHTML5 (XML-serialized HTML5) :

Differences from HTML 4.01 and XHTML 1.x :

• New parsing rules: oriented towards flexible parsing and compatibility; not based on SGML

• Ability to use inline SVG and MathML in text/html

• New elements: article, aside, audio, bdi, canvas, command, data, datalist, details, embed, figcaption, figure, footer, header, keygen,mark, meter, nav, output, progress, rp, rt, ruby, section, source, summary, time, track, video, wbr

• New types of form controls: dates and times, email, url, search, number, range, tel, color^[72]

• New attributes: charset (on meta), async (on script)

• Global attributes (that can be applied for every element): id, tabindex, hidden, data-* (custom data attributes)

• Deprecated elements will be dropped altogether: acronym, applet, basefont, big, center, dir, font, frame, frameset, isindex, noframes, strike, tt

The W3C proposed a greater reliance on modularity as a key part of the plan to make faster progress, meaning identifying specific features, either proposed or already existing in the spec, and advancing them as separate specifications. Some technologies that were originally defined in HTML5 itself are now defined in separate specifications:

After the standardization of the HTML5 specification in October 2014, the core vocabulary and features are being extended in four ways. Some parts of HTML5 that have been removed from the original HTML5 specification are standardized separately as modules (APIs) such as Microdata and Canvas. Technical specifications introduced as HTML5 extensions such as Polyglot Markup are also standardized as modules. Some W3C specifications that have originally been separate specifications are adapted as HTML5 extensions or features, as for example, SVG. The specific features that would have slowed down the standardization of HTML5 will be standardized as upcoming specifications such as HTML 5.1, HTML 5.2, and so on. HTML 5.1 is expected to be finalized in 2016, and it is currently on the standardization track at the W3C.

HTML5 introduces elements and attributes that reflect typical usage on modern websites. Some of them are semantic replacements for common uses of generic block (<div>) and inline (<span>) elements, for example <nav> (website navigation block), <footer> (usually referring to bottom of web page or to last lines of HTML code), or <audio>and <video> instead of <object>.Some deprecated elements from HTML 4.01 have been dropped, including purely presentational elements such as <font> and<center>, whose effects have long been superseded by the more capable Cascading Style Sheets. There is also a renewed emphasis on the importance of DOM scripting(e.g., JavaScript) in Web behavior.

The HTML5 syntax is no longer based on SGML despite the similarity of its markup. It has, however, been designed to be backward compatible with common parsing of older versions of HTML. It comes with a new introductory line that looks like an SGML document type declaration, <!DOCTYPE html>, which triggers the standards-compliantrendering mode. Since 5 January 2009, HTML5 also includes Web Forms 2.0, a previously separate WHATWG specification.

In addition to specifying markup, HTML5 specifies scripting application programming interfaces (APIs) that can be used with JavaScript. Existing document object model(DOM) interfaces are extended and de facto features documented. There are also new APIs, such as:

Not all of the above technologies are included in the W3C HTML5 pecification, though they are in the WHATWG HTML specification. Some related technologies, which are not part of either the W3C HTML5 or the WHATWG HTML specification, are as follows. The W3C publishes specifications for these separately:

HTML5 cannot provide animation within web pages. Additional JavaScript or CSS3 functionality is necessary for animating HTML elements. Animation is also possible using JavaScript and HTML 4, and within SVG elements through SMIL, although browser support of the latter remains uneven as of 2011.

XML documents must be served with an XML Internet media type (often called "MIME type") such as application/xhtml+xml or application/xml, and must conform to strict, well-formed syntax of XML. XHTML5 is simply an XML-serialized HTML5 data (e.g. not having any unclosed tags), sent with one of XML media types. HTML that has been written to conform to both the HTML and XHTML specifications – and which will therefore produce the same DOM tree whether parsed as HTML or XML – is termed "polyglot markup".

HTML5 is designed so that old browsers can safely ignore new HTML5 constructs. In contrast to HTML 4.01, the HTML5 specification gives detailed rules for lexing andparsing, with the intent that different compliant browsers will produce the same result in the case of incorrect syntax.Although HTML5 now defines a consistent behavior for "tag soup" documents, those documents are not regarded as conforming to the HTML5 standard.