XHTML (Extensible Hypertext Markup Language) is a family of XML Extensible Markup Language 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 markup languages A markup language is a modern system for annotating a text in a way that is syntactically distinguishable from that text. The idea and terminology evolved from the "marking up" of manuscripts, i.e. the revision instructions by editors, traditionally written with a blue pencil on authors' manuscripts. Examples are typesetting instructions that mirror or extend versions of the widely used Hypertext Markup Language HTML, which stands for HyperText Markup Language, is the predominant markup language for web pages. It provides a means to create structured documents by denoting structural semantics for text such as headings, paragraphs, lists etc as well as for links, quotes, and other items. It allows images and objects to be embedded and can be used to create (HTML), the language in which web pages A web page or webpage is a document or resource of information that is suitable for the World Wide Web and can be accessed through a web browser and displayed on a monitor or mobile device are written.
While HTML (prior to HTML5 HTML5 is currently under development as the next major revision of the HTML standard. Like its immediate predecessors, HTML 4.01 and XHTML 1.1, HTML5 is a standard for structuring and presenting content on the World Wide Web. The new standard incorporates features like video playback and drag-and-drop that have been previously dependent on third-) was defined as an application of Standard Generalized Markup Language The Standard Generalized Markup Language is an ISO-standard technology for defining generalized markup languages for documents. ISO 8879 Annex A.1 defines generalized markup: (SGML), a very flexible markup language framework, XHTML is an application of XML Extensible Markup Language 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, a more restrictive subset of SGML. Because XHTML documents need to be well-formed Extensible Markup Language 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, they can be parsed using standard XML parsers—unlike HTML, which requires a lenient HTML-specific parser In computer science and linguistics, parsing, or, more formally, syntactic analysis, is the process of analyzing a text, made of a sequence of tokens , to determine its grammatical structure with respect to a given (more or less) formal grammar.
XHTML 1.0 became a World Wide Web Consortium The World Wide Web Consortium is the main international standards organization for the World Wide Web (abbreviated WWW or W3) (W3C) Recommendation A W3C Recommendation is the final stage of a ratification process of the World Wide Web Consortium working group concerning the standard. This designation signifies that a document has been subjected to a public and W3C-member organization's review. It aims to standardise the Web technology. It is the equivalent of a published standard in many on January 26, 2000. XHTML 1.1 became a W3C Recommendation on May 31, 2001. XHTML5 XHTML5 is the XML serialisation of HTML5. XHTML5 must be served with an XML MIME type: application/xhtml+xml . XHTML5 requires strict well-formed syntax is undergoing development as of September 2009, as part of the HTML5 HTML5 is currently under development as the next major revision of the HTML standard. Like its immediate predecessors, HTML 4.01 and XHTML 1.1, HTML5 is a standard for structuring and presenting content on the World Wide Web. The new standard incorporates features like video playback and drag-and-drop that have been previously dependent on third- specification.
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Overview
XHTML 1.0 is "a reformulation of the three HTML 4 document types as applications of XML 1.0".[1] The World Wide Web Consortium The World Wide Web Consortium is the main international standards organization for the World Wide Web (abbreviated WWW or W3) (W3C) also continues to maintain the HTML 4.01 Recommendation, and the specifications for HTML5 HTML5 is currently under development as the next major revision of the HTML standard. Like its immediate predecessors, HTML 4.01 and XHTML 1.1, HTML5 is a standard for structuring and presenting content on the World Wide Web. The new standard incorporates features like video playback and drag-and-drop that have been previously dependent on third- and XHTML5 are being actively developed. In the current XHTML 1.0 Recommendation document, as published and revised to August 2002, the W3C commented that, "The XHTML family is the next step in the evolution of the Internet. By migrating to XHTML today, content developers can enter the XML world with all of its attendant benefits, while still remaining confident in their content's backward and future compatibility."[1]
However, in 2004, the Web Hypertext Application Technology Working Group The Web Hypertext Application Technology Working Group, or WHATWG, is a community of people interested in evolving HTML and related technologies. The WHATWG was founded by individuals from Apple, the Mozilla Foundation and Opera Software. Since then, the editor of the WHATWG specifications, Ian Hickson, has moved to Google. Chris Wilson of (WHATWG) formed, independently of the W3C, to work on advancing ordinary HTML not based on XHTML. Most major browser vendors were unwilling to implement the features in new W3C XHTML 2.0 drafts, and felt that they didn't serve the needs of modern web development.[citation needed] The WHATWG eventually began working on a standard that supported both XML and non-XML serializations In computer science, in the context of data storage and transmission, serialization is the process of converting a data structure or object into a sequence of bits so that it can be stored in a file or memory buffer, or transmitted across a network connection link to be "resurrected" later in the same or another computer environment, HTML 5 HTML5 is currently under development as the next major revision of the HTML standard. Like its immediate predecessors, HTML 4.01 and XHTML 1.1, HTML5 is a standard for structuring and presenting content on the World Wide Web. The new standard incorporates features like video playback and drag-and-drop that have been previously dependent on third-, in parallel to W3C standards such as XHTML 2. In 2007, the W3C's HTML working group voted to officially recognize HTML 5 and work on it as the next-generated HTML standard.[2] In 2009, the W3C allowed the XHTML 2 Working Group's charter to expire, acknowledging that HTML 5 would be the sole next-generation HTML standard, including both XML and non-XML serializations.[3]
Motivation
XHTML was developed to make HTML more extensible In software engineering, extensibility is a system design principle where the implementation takes into consideration future growth. It is a systemic measure of the ability to extend a system and the level of effort required to implement the extension. Extensions can be through the addition of new functionality or through modification of existing and increase interoperability Interoperability is a property referring to the ability of diverse systems and organizations to work together . The term is often used in a technical systems engineering sense, or alternatively in a broad sense, taking into account social, political, and organizational factors that impact system to system performance with other data formats.[4] HTML 4 was ostensibly an application of Standard Generalized Markup Language The Standard Generalized Markup Language is an ISO-standard technology for defining generalized markup languages for documents. ISO 8879 Annex A.1 defines generalized markup: (SGML); however the specification for SGML was complex, and neither web browsers nor the HTML 4 Recommendation were fully conformant to it.[5] The XML standard, approved in 1998, provided a simpler data format closer in simplicity to HTML 4.[6] By shifting to an XML format, it was hoped HTML would become compatible with common XML tools;[7] servers and proxies would be able to transform content, as necessary, for constrained devices such as mobile phones.[8] By utilizing namespaces XML namespaces are used for providing uniquely named elements and attributes in an XML document. They are defined in Namespaces in XML, a W3C recommendation. An XML instance may contain element or attribute names from more than one XML vocabulary. If each vocabulary is given a namespace then the ambiguity between identically named elements or, XHTML documents could provide extensibility by including fragments from other XML-based languages such as Scalable Vector Graphics Scalable Vector Graphics is a family of specifications of an XML-based file format for describing two-dimensional vector graphics, both static and dynamic (i.e. interactive or animated) and MathML Mathematical Markup Language is an application of XML for describing mathematical notations and capturing both its structure and content. It aims at integrating mathematical formulae into World Wide Web pages and other documents. It is a recommendation of the W3C math working group.[9] Finally, the renewed work would provide an opportunity to divide HTML into reusable components (XHTML Modularization XHTML modularization is a methodology for producing modularized markup languages in a number of different schema languages so that the modules can easily be plugged together to create markup languages) and clean up untidy parts of the language.[10]
Relationship to HTML
There are various differences between XHTML and HTML. The Document Object Model The Document Object Model is a cross-platform and language-independent convention for representing and interacting with objects in HTML, XHTML and XML documents. Aspects of the DOM (such as its "Elements") may be addressed and manipulated within the syntax of the programming language in use. The public interface of a DOM are specified in is a tree structure which represents the page internally in applications, and XHTML and HTML are two different ways of representing that in markup (serialisations). Both are less expressive than the DOM (for example, "--" may be placed in comments in the DOM, but cannot be represented in a comment in either XHTML or HTML), and generally XHTML's XML syntax is a little more expressive than HTML (for example, arbitrary namespaces are not allowed in HTML). So, firstly one source of differences is immediate: XHTML uses an XML syntax, while HTML uses a pseudo-SGML The Standard Generalized Markup Language is an ISO-standard technology for defining generalized markup languages for documents. ISO 8879 Annex A.1 defines generalized markup: syntax (officially SGML for HTML 4 and under, but never in practice, and standardised away from SGML in HTML5). Secondly however, because the expressible contents of the DOM in syntax are slightly different, there are some changes in actual behaviour between the two models.
Firstly then, syntax differences:[11]
- Broadly, the XML rules require that all elements be closed, either by a separate closing tag or using self closing syntax (e.g.
<br/>), while HTML syntax permits some elements to be unclosed because either they are always empty (e.g.<input>) or their end can be determined implicitly ("omissibility", e.g.<p>). - XML is case-sensitive for element and attribute names, while HTML is not.
- Some shorthand features in HTML are omitted in XML, such as (1) attribute minimization, where attribute values or their quotes may be omitted (e.g.
<option selected>or<option selected=selected>, while XML this must be expressed as<option selected="selected">); (2) element minimization may be used to remove elements entirely (such as<tbody>inferred in a table if not given); and (3) the rarely used SGML syntax for element minimization ("shorttag"), which most browsers do not implement. - There are numerous other technical requirements surrounding namespaces and precise parsing of whitespace and certain characters and elements. The exact parsing of HTML in practice has been undefined until recently; see the HTML5 specification ([HTML5]) for full details, or the working summary (HTML vs. XHTML).
Secondly, in contrast to these syntactical differences which are minor, there are some behavioural differences. Most of these arise from the underlying differences in serialisation. For example:
- Most prominently, behaviour on parse errors differ. A fatal parse error in XML (such as an incorrect tag structure) causes document processing to be aborted (a "yellow screen of death").
- Most content requiring namespaces will not work in HTML, except the built-in support for SVG and MathML in the HTML5 parser along certain magic prefixes such as
xlink. - JavaScript processing is a little different, with minor changes in case sensitivity to some functions, and further precautions in XHTML to restrict processing well-formed to well-formed content. Third-party scripts, such as sidebars proving live feeds or Google's "web clips", often rely on the
document.write()method, which is not available in XHTML pages so the scripts fail on pages served as XHTML (that is, using an XML MIME type). TheinnerHTMLproperty is available on XML pages, but uses the same XML parser as the whole page, so will not insert content if a non-well-formed string is passed. More positively,innerHTMLin XHTML can be used to insert namespaced content to the page. - CSS is also applied slightly differently too, with case-sensitivity and some differences in handling of backgrounds on
<html>and<body>in XHTML and HTML.[12]
Adoption
The similarities between HTML 4.01 and XHTML 1.0 led many web sites and content management systems to adopt the initial W3C XHTML 1.0 Recommendation. To aid authors in the transition, the W3C provided guidance on how to publish XHTML 1.0 documents in an HTML-compatible manner, and serve them to browsers that were not designed for XHTML.[13][14]
Such "HTML-compatible" content is sent using the HTML media type (text/html) rather than the official Internet media type for XHTML (application/xhtml+xml). When measuring the adoption of XHTML to that of regular HTML, therefore, it is important to distinguish whether it is media type usage or actual document contents that is being compared.
Most web browsers have mature support[15] for all of the possible XHTML media types.[16] The notable exception is Internet Explorer Windows Internet Explorer , is a series of graphical web browsers developed by Microsoft and included as part of the Microsoft Windows line of operating systems starting in 1995. It has been the most widely used web browser since 1999, attaining a peak of about 95% usage share during 2002 and 2003 with IE5 and IE6 by Microsoft Microsoft Corporation is a public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions. Established on April 4, 1975 to develop and sell BASIC interpreters for the Altair 8; rather than rendering application/xhtml+xml content, a dialog box invites the user to save the content to disk instead. Both Internet Explorer 7 (released in 2006) and Internet Explorer 8 (released in March 2009) exhibit this behavior.[17] Microsoft developer Chris Wilson explained in 2005 that IE7’s priorities were improved security and CSS Cascading Style Sheets is a style sheet language used to describe the presentation semantics (that is, 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 SVG and XUL support, and that proper XHTML support would be difficult to graft onto IE’s compatibility-oriented HTML parser[18]; however, Microsoft Microsoft Corporation is a public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions. Established on April 4, 1975 to develop and sell BASIC interpreters for the Altair 8 has added support for true XHTML in current developer previews of IE9 Internet Explorer 9 is the upcoming version of the Internet Explorer web browser from Microsoft. It is currently in development, but developer previews have been released.[19]
As long as support is not widespread, most web developers avoid using XHTML that isn’t HTML-compatible,[20] so advantages of XML such as namespaces, faster parsing and smaller-footprint browsers do not benefit the user.
Criticism
In the early 2000s, some web developers began to question why Web authors ever made the leap into authoring in XHTML.[21][22][23] Others countered that the problems ascribed to the use of XHTML could mostly be attributed to two main sources: the production of invalid XHTML documents by some Web authors and the lack of support for XHTML built into Internet Explorer 6 Internet Explorer 6 is the sixth major revision of Internet Explorer, a web browser developed by Microsoft for Windows operating systems. It was released on August 27, 2001, shortly after the completion of Windows XP.[24][25] They went on to describe the benefits of XML-based Web documents (i.e. XHTML) regarding searching, indexing and parsing as well as future-proofing the Web itself.
In October 2006, HTML inventor and W3C chair Tim Berners-Lee Sir Timothy John "Tim" Berners-Lee, OM, KBE, FRS, FREng, FRSA , is a British engineer and computer scientist and MIT professor credited with inventing the World Wide Web, making the first proposal for it in March 1989. On 25 December 1990, with the help of Robert Cailliau and a young student at CERN, he implemented the first successful, introducing a major W3C effort to develop new HTML 5 HTML5 is currently under development as the next major revision of the HTML standard. Like its immediate predecessors, HTML 4.01 and XHTML 1.1, HTML5 is a standard for structuring and presenting content on the World Wide Web. The new standard incorporates features like video playback and drag-and-drop that have been previously dependent on third- and XHTML 5 specifications, posted in his blog that, "The attempt to get the world to switch to XML … all at once didn't work. The large HTML-generating public did not move … Some large communities did shift and are enjoying the fruits of well-formed systems … The plan is to charter a completely new HTML group."[26] In the current HTML and XHTML 5 working draft, its authors say that, "special attention has been given to defining clear conformance criteria for user agents in an effort to improve interoperability … while at the same time updating the HTML specifications to address issues raised in the past few years." Ian Hickson Ian 'Hixie' Hickson is the author and maintainer of the Acid2 and Acid3 tests, and the Web Applications 1.0/HTML 5 specification. He is known as a proponent of web standards, and has played a crucial role in the development of specifications such as CSS.[citation needed] Hickson was a co-editor of the CSS 2.1 specification, author of a paper criticising the improper use of XHTML in 2002,[21] is a member of the group developing this specification and is listed as one of the co-authors of the current working draft.[27]
Simon Pieters researched the XML-compliance of mobile browsers[28] and concluded “the claim that XHTML would be needed for mobile devices is simply a myth”.
Versions of XHTML
Thu, 05 Aug 2010 06:56:32 GMT+00:00
FPRD (press release) (blog) It has an WAP 2.0 / xHTML (NetFront) browser that gives you internet access no matter where you go,so you are always connected to your family and friends ...
330px x 778px | 199.10kB
[source page]
hint this is very similar to what you did in hw4
tarantinoon
Wed, 18 Aug 2010 07:00:00 GM
Dynamic . XHTML. Corporate - Bestwork Dynamic . XHTML. Corporate - Bestwork Dynamic . XHTML. Corporate - Bestwork DreamTemplate | . XHTML. | CSS | Tableless | PSD | 14.7MB Demo: http:www.dre.
