Hypertext is text displayed on a computer or other electronic device with references (hyperlinks) to other text that the reader can immediately access, usually by a mouse click or keypress sequence. Apart from running text, hypertext may contain tables, images and other presentational devices. Hypertext is the underlying concept defining the structure of the World Wide Web. It is an easy-to-use and flexible format to share information over the Internet.
Hypertext documents can either be static (prepared and stored in advance) or dynamic (continually changing in response to user input). Static hypertext can be used to cross-reference collections of data in documents, software applications, or books on CDs. A well-constructed system can also incorporate other user-interface conventions, such as menus and command lines. Hypertext can develop very complex and dynamic systems of linking and cross-referencing. The most famous implementation of hypertext is the World Wide Web, first deployed in 1992.
Hypermedia is not constrained to be text based, it includes other media also like graphics,images, sound and video.It is a computer-based information retrieval system that enables a user to gain or provide access to texts, audio and video recordings, photographs and computer graphics related to a particular subject. Hypermedia is a term created by Ted Nelson. Hypermedia is used as a logical extension of the term hypertext in which graphics, audio, video, plain text and hyperlinks intertwine to create a generally non-linear medium of information. This contrasts with the broader term multimedia, which may be used to describe non-interactive linear presentations as well as hypermedia. It is also related to the field of Electronic literature. The term was first used in a 1965 article by Ted Nelson.
A book is in linear format, but Hypermedia is non linear, through hotspots or hyperlinks there is non-linearity.
The World Wide Web is a classic example of hypermedia, whereas a non-interactive cinema presentation is an example of standard multimedia due to the absence of hyperlinks.
Hypermedia may be developed a number of ways. Any programming tool can be used to write programs that link data from internal variables and nodes for external data files. Multimedia development software such as Adobe Flash, Adobe Director, Macromedia Authorware, and MatchWare Mediator may be used to create stand-alone hypermedia applications, with emphasis on entertainment content. Some database software such as Visual FoxPro and FileMaker Developer may be used to develop stand-alone hypermedia applications, with emphasis on educational and business content management.
Hypermedia applications may be developed on embedded devices for the mobile and the Digital signage industries using the Scalable Vector Graphics (SVG) specification from W3C (World Wide Web Consortium). Software applications such as Ikivo Animator and Inkscape simplify the development of Hypermedia content based on SVG. Embedded devices such as iPhone natively support SVG specifications and may be used to create mobile and distributed Hypermedia applications.
Hyperlinks may also be added to data files using most business software via the limited scripting and hyperlinking features built in. Documentation software such as the Microsoft Office Suite and LibreOffice allow for hypertext links to other content within the same file, other external files, and URL links to files on external file servers. For more emphasis on graphics and page layout, hyperlinks may be added using most modern desktop publishing tools. This includes presentation programs, such as Microsoft Powerpoint and LibreOffice Impress, add-ons to print layout programs such as Quark Immedia, and tools to include hyperlinks in PDF documents such as Adobe InDesign for creating and Adobe Acrobat for editing. Hyper Publish is a tool specifically designed and optimized for hypermedia and hypertext management. Any HTML Editor may be used to build HTML files, accessible by any web browser. CD/DVD authoring tools such as DVD Studio Pro may be used to hyperlink the content of DVDs for DVD players or web links when the disc is played on a personal computer connected to the internet.
http stands for Hype text transfer protocol. HyperText Transfer Protocol, the underlying protocol used by the World Wide Web. HTTP defines how messages are formatted and transmitted, and what actions Web servers and browsers should take in response to various commands. For example, when you enter a URL in your browser, this actually sends an HTTP command to the Web server directing it to fetch and transmit the requested Web page.HTTP functions as a request-response protocol in the client-server computing model. In HTTP, a web browser, for example, acts as a client, while an application running on a computer hosting a web site functions as a server. The client submits an HTTP request message to the server. The server, which stores content, or provides resources, such as HTML files, or performs other functions on behalf of the client, returns a response message to the client. A response contains completion status information about the request and may contain any content requested by the client in its message body.
A web browser (or client) is often referred to as a user agent (UA). Other user agents can include the indexing software used by search providers, known as web crawlers, or variations of the web browser such as voice browsers, which present an interactive voice user interface.
The HTTP protocol is designed to permit intermediate network elements to improve or enable communications between clients and servers. High-traffic websites often benefit from web cache servers that deliver content on behalf of the original, so-called origin server, to improve response time. HTTP proxy servers at network boundaries facilitate communication when clients without a globally routable address are located in private networks by relaying the requests and responses between clients and servers.
HTTP is an Application Layer protocol designed within the framework of the Internet Protocol Suite. The protocol definitions presume a reliable Transport Layer protocol for host-to-host data transfer. The Transmission Control Protocol (TCP) is the dominant protocol in use for this purpose. However, HTTP has found application even with unreliable protocols, such as the User Datagram Protocol (UDP) in methods such as the Simple Service Discovery Protocol (SSDP).
HTTP Resources are identified and located on the network by Uniform Resource Identifiers (URIs)—or, more specifically, Uniform Resource Locators (URLs)—using the http or https URI schemes. URIs and the Hypertext Markup Language (HTML), form a system of inter-linked resources, called hypertext documents, on the Internet, that led to the establishment of the World Wide Web in 1990 by English computer scientist and innovator Tim Berners-Lee.
- It is a protocol designed to transmit hypermedia.
- It supports transmission of any file type.
- It is a stateless request / response protocol, in the sense that a client typically opens a connection to the http server, requests information, server responds and the connection is terminated. HTTP is called a stateless protocol because each command is executed independently, without any knowledge of the commands that came before it.
HyperText Markup Language (HTML) is the predominant markup language for web pages. HTML elements are the basic building-blocks of webpages.
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 , although some tags, known as empty elements, are unpaired. The first tag in a pair is the start tag, 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, 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 is a language for describing web pages.
- HTML is the language for publishing hypemedia on WWW.
- HTML covers how Web pages are formatted and displayed.
- HTML stands for Hyper Text Markup Language
- HTML is not a programming language, it is a markup language
- A markup language is a set of markup tags
- HTML uses markup tags to describe web pages
- HTML documents describe web pages
- HTML documents contain HTML tags and plain text
- HTML documents are also called web pages
The purpose of a web browser (like Internet Explorer or Firefox) is to read HTML documents and display them as web pages. The browser does not display the HTML tags, but uses the tags to interpret the content of the page
Cascading Style Sheets (CSS) is a style sheet language used to describe the presentation semantics (the look and formatting) of a document written in a markup language. Its most common application is to style web pages written in HTML and XHTML, but the language can also be applied to any kind of XML document, including plain XML, SVG and XUL.
CSS is designed primarily to enable the separation of document content (written in HTML or a similar markup language) from document presentation, including elements such as the layout, colors, and fonts. This separation can improve content accessibility, provide more flexibility and control in the specification of presentation characteristics, enable multiple pages to share formatting, and reduce complexity and repetition in the structural content (such as by allowing for tableless web design). CSS can also allow the same markup page to be presented in different styles for different rendering methods, such as on-screen, in print, by voice (when read out by a speech-based browser or screen reader) and on Braille-based, tactile devices. While the author of a document typically links that document to a CSS style sheet, readers can use a different style sheet, perhaps one on their own computer, to override the one the author has specified.
CSS specifies a priority scheme to determine which style rules apply if more than one rule matches against a particular element. In this so-called cascade, priorities or weights are calculated and assigned to rules, so that the results are predictable.
The CSS specifications are maintained by the World Wide Web Consortium (W3C). Internet media type (MIME type) text/css is registered for use with CSS by RFC 2318 (March 1998).
XML is Extensible Markup Language.Extensible Markup Language (XML) is a set of rules for encoding documents in machine-readable form. It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications, all gratis open standards.
The design goals of XML emphasize simplicity, generality, and usability over the Internet.It is a textual data format with strong support via Unicode for the languages of the world. Although the design of XML focuses on documents, it is widely used for the representation of arbitrary data structures, for example in web services.
Many application programming interfaces (APIs) have been developed that software developers use to process XML data, and several schema systems exist to aid in the definition of XML-based languages.
As of 2009[update], hundreds of XML-based languages have been developed, including RSS, Atom, SOAP, and XHTML. XML-based formats have become the default for most office-productivity tools, including Microsoft Office (Office Open XML), OpenOffice.org (OpenDocument), and Apple's iWork.
Synchronized Multimedia Integration Language, is a W3C recommended XML markup language for describing multimedia presentations. It defines markup for timing, layout, animations, visual transitions, and media embedding, among other things. SMIL allows the presentation of media items such as text, images, video, and audio, as well as links to other SMIL presentations, and files from multiple web servers. SMIL markup is written in XML, and has similarities to HTML.
A SMIL document is similar in structure to an HTML document in that
- They are typically divided between an optional <head> section and a required <body> section.
- The <head> section contains layout and metadata information.
- The <body> section contains the timing information, and is generally composed of combinations of three main tags -
- sequential ("<seq>", simple playlists),
- parallel ("<par>", multi-zone/multi-layer playback) and exclusive ("<excl>",
- event-triggered interrupts).
- SMIL refers to media objects by URLs, allowing them to be shared between presentations and stored on different servers for load balancing. *The language can also associate different media objects with different bandwidth requirements.
- SMIL files commonly use the .smil file extension to avoid confusion.
Combination with other XML-based standards
While (RSS) and (Atom) are web syndication methods, with the former being more popular as a syndication method for podcasts, SMIL is potentially useful as a script or playlist that can tie sequential pieces of multimedia together and can then be syndicated through RSS or Atom.
In addition, the combination of multimedia-laden .smil files with RSS or Atom syndication would be useful for accessibility to audio-enabled podcasts by the deaf through Timed Text closed captions,
SMIL+VoiceXML and SMIL+MusicXML
VoiceXML can be combined with SMIL to provide a sequential reading of several pre-provided pages or slides in a voice browser, while combining SMIL with MusicXML would allow for the creation of infinitely-recombinable sequences of music sheets. Combining SMIL+VoiceXML or SMIL+MusicXML with RSS or Atom could be useful in the creation of an audible pseudo-podcast with embedded hyperlinks, while combining SMIL+SVG with VoiceXML and/or MusicXML would be useful in the creation of an automatically audio-enabled vector graphics animation with embedded hyperlinks.
SMIL is anticipated for use within Text Encoding Initiative(TEI) documents.
SMIL in HD DVD, Digital Signage
SMIL is also one of the underlying technologies used by HD DVD for advanced interactivity.
The field of Digital Signage is embracing SMIL as a means of controlling dynamic advertising in public areas.
The internet video site Hulu uses SMIL as part of its media playing technology.
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