Markup Languages Web Development Standard Generalised Markup Language
Markup Languages Web Development
Standard Generalised Markup Language (SGML) � SGML is a metalanguage which means that it is used to create other languages – including HTML and x. HTML � Originally created by IBM � Standardised in 1986 by the International Organization for Standardisation (ISO) � Powerful markup language that describes document information � Very complex and difficult to learn
Standard Generalised Markup Language (SGML) � Standard Generalized Markup Language (SGML): A metalanguage used to create other languages, including XML, HTML and XHTML. � Metalanguage: A language used for defining other languages.
Standard Generalised Markup Language (SGML) � SGML requires that you create your own document language rules. � This set of rules is called the Document Type Definition (DTD). � The DTD is generally specified in a separate file which you reference, or declare, at the beginning of each document. � Once declared, all document elements must conform to this DTD.
Standard Generalised Markup Language (SGML) � Document Type Definition (DTD): A set of rules contained in a simple text file that defines the structure, syntax and vocabulary as it relates to tags and attributes for a corresponding document.
Standard Generalised Markup Language (SGML) � Document Type Declaration (<!DOCTYPE>): A declaration of document or code type embedded within an HTML, XML or SGML document. Identifies the version and markup language used. Denoted by the <!DOCTYPE> declaration at the beginning of the document.
Document Type Declaration (<!DOCTYPE>) � Describes the markup language and version of your code � Placed at the top of the document � If you do not specify a <!DOCTYPE> declaration, then two problems may arise: ◦ You will not be able to control how your code renders in the future ◦ You will not be able to use a markup validator � Each version and flavor of HTML/XHTML has its own <!DOCTYPE> declaration � <!DOCTYPE html> is used for HTML 5 files
Document Structure Tags
Hypertext Markup Language (HTML) � Developed by Tim Berners-Lee at CERN (European Particle Physics Laboratory) as a means of distributing non-linear text – called hypertext to multiple points across the Internet. � Needed a cross-platform language that helped format documents. SGML was too complex.
Hypertext Markup Language (HTML) � HTML does not allow you to define a DTD � Also fewer languages elements than SGML � Easier to use than SGML � The global set of linked documents across the existing Internet framework grew into the World Wide Web. � HTML became the standard method of encoding web documents
Hypertext Markup Language (HTML) � HTML 5 is not based on SGML � Allows the simplification of HTML structure � The DTD is not required
What is W 3 C? � Stands for the World Wide Web Consortium (http: //www. w 3. org/) � Created in October 1994 by Tim Berners-Lee � Is organized as a ‘Member Organization’ � Aim is to standardize the Web � Creates and maintains WWW Standards � Standards are called W 3 C Recommendations
How it Started � The World Wide Web began as a project at the European Organization for Nuclear Research (CERN), where Tim Berners-Lee developed a vision of the World Wide Web. � Tim Berners-Lee - the inventor of the World Wide Web - is now the Director of the World Wide Web Consortium (W 3 C).
How it Started � W 3 C was created in 1994 as a collaboration between the Massachusetts Institute of Technology (MIT) and the European Organization for Nuclear Research (CERN), with support from the U. S. Defense Advanced Research Project Agency (DARPA) and the European Commission.
Standardizing the Web � The W 3 C mission is to lead the World Wide Web to its full potential by developing protocols and guidelines that ensure the long-term growth of the Web.
Standardizing the Web � W 3 C is working to make the Web accessible to all users (despite differences in hardware, software, network infrastructure, native language, culture, education, geographical location, and physical or mental ability) � W 3 C also coordinates its work with many other standards organizations such as the Internet Engineering Task Force, the Wireless Application Protocols (WAP) Forum and the Unicode Consortium.
W 3 C Members � Because the Web is so important (both in scope and in investment) that no single organization should have control over its future, W 3 C functions as a member organization. � Some ◦ ◦ well known members are: IBM Microsoft America Online Apple
W 3 C Members ◦ Adobe ◦ Macromedia ◦ Sun Microsystems � The Full List of Member Organizations includes a variety of software vendors, content providers, corporate users, telecommunications companies, academic institutions, research laboratories, standards bodies, and governments.
W 3 C Recommendations � The most important work done by the W 3 C is the development of Web specifications (called "Recommendations") which describe communication protocols (like HTML and XML) and other building blocks of the Web.
W 3 C HTML Activities HTML is the universal markup language for the Web.
HTML Versions – HTML 2. 0 � HTML 2. 0 was developed by the Internet Engineering Task Force HTML Working Group in 1996. � HTML 2. 0 is an outdated version of HTML. � For a Web developer there is no need to study the HTML 2. 0 standard.
HTML 3. 2 and HTML 4. 01 � HTML 3. 2 is an older but functional HTML standard. � Some web pages and HTML editors still use the 3. 2 standard as well as the 4. 01 standard.
HTML Versions – HTML 3. 2 � HTML 3. 2 became a W 3 C Recommendation 14 January 1997. � HTML 3. 2 added new features such as fonts, tables, applets, superscripts, subscripts (and more) to the existing HTML 2. 0 standard.
HTML Versions – HTML 3. 2 � One of the elements added to the HTML 3. 2 standard, was the <font> tag. � This tag introduced unnecessary complexity to the important task of separating HTML content (text) from its presentation (style). � The <font> tag became deprecated in HTML 4. 0.
HTML Versions – HTML 4. 0 � HTML 4. 0 became a W 3 C Recommendation 18 December 1997. � A second release was issued on 24 April 1998 with only some editorial corrections. � The most important feature of HTML 4. 0 was the introduction of style sheets (CSS).
HTML Versions – HTML 4. 01 � HTML 4. 01 became a W 3 C Recommendation 24. December 1999. � HTML 4. 01 was a minor update of corrections and bug-fixes from HTML 4. 0.
Hypertext Markup Language (HTML) � HTML 4. 01 flavors include: ◦ 4. 01 Strict – requires all container tags and does not allow deprecated tags ◦ 4. 01 Transitional – allows deprecated tags, not as strict ◦ 4. 01 Frameset – for use with frames
HTML Versions – XHTML 1. 0 �XHTML 1. 0 reformulates HTML 4. 01 in XML. �XHTML 1. 0 became a W 3 C Recommendation 20 January 2000.
HTML Versions – HTML 5 � On January 22 2008, W 3 C published a working draft for HTML 5. � HTML 5 improves interoperability, and reduces development costs, by making precise rules on how to handle all HTML elements, and how to recover from errors.
HTML Versions – HTML 5 � Some of the new features in HTML 5 are functions for embedding audio, video, graphics, client-side data storage, and interactive documents. � HTML 5 also contains new elements like <nav>, <header>, <footer>, and <figure>. � The HTML 5 working group includes AOL, Apple, Google, IBM, Microsoft, Mozilla, Nokia, Opera, and many hundred other vendors.
HTML Versions – HTML 5 � Offline Storage: The ability for Web browsers and online services to download and access content and services without being connected to the Internet. � Geolocation: An HTML 5 Application Programming Interface (API) that allows developers to retrieve the geographical location information for a client-side device.
W 3 C HTML Specifications and Timeline Specification HTML 3. 2 HTML 4. 01 HTML 5 Recommendation 14. January 1997 24. April 1998 24. December 1999 19. October 2010 (latest draft)
W 3 C XHTML Activities XHTML is a stricter and cleaner version of HTML.
Extensible Hypertext Markup Language (x. HTML) � Extensible Hypertext Markup Language (XHTML) ◦ Combines HTML with XML � XHTML 1. 0 flavors include: ◦ Transitional – allows deprecated tags, not as strict ◦ Strict – requires the exclusive use of CSS for all formatting elements and does not allow deprecated tags ◦ Frameset – for use with frames � XHTML allows HTML to become XML-compliant
XHTML Versions – 1. 0 XHTML 1. 0 � XHTML 1. 0 became a W 3 C Recommendation 20 January 2000. XHTML 1. 0 Second Edition � XHTML 1. 0 Second Edition became a W 3 C Recommendation 1 August 2002. The second edition was not a new version, but an update and a "bug-fix".
About XHTML 1. 0 � XHTML 1. 0 was the first major change to HTML since 1997. � XHTML was an important step for creating a standard that provided richer web pages on a wider range of user agents (browsers), like desktop PCs, mobile (wireless) devices, and cell phones.
About XHTML 1. 0 � XHTML 1. 0 reformulates HTML 4. 01 in XML. XHTML 1. 0 relies on HTML 4. 01 for the meanings of the HTML tags. � W 3 C's next step included modularization of XHTML into smaller element collections, to make it easier to combine XHTML with other markup languages, like vector graphics or multimedia.
About XHTML 1. 0 � Modularization of XHTML reduced development costs, improved cooperation with other applications (like databases), easier communication with different user agents, and cleaner integration between HTML and different XML standards.
W 3 C XML Activities � XML was designed to transport and store data.
Extensible Markup Language (XML) � Extensible Markup Language (XML) ◦ A subset of SGML, also a metalanguage ◦ XML describes data instead of formatting ◦ HTML or XHTML provides formatting and document structure � XML documents have a tree structure � XML documents must be well-formed � XML and valid documents: the DTD � XML and style sheets
Extensible Markup Language (XML) � Extensible Markup Language (XML): A markup language that describes document content instead of adding structure or formatting to document content. A simplified version of SGML.
XML Versions – XML 1. 0 and 1. 1 XML 1. 0 � XML 1. 0 became a W 3 C Recommendation 10. February 1998. XML 1. 0 (Second Edition) � XML 1. 0 (SE) became a W 3 C Recommendation 6. October 2000. The second edition is not a new version, but an update and a "bug-fix“.
W 3 C CSS Activities � CSS defines how HTML elements are to be displayed.
CSS Versions CSS 1 � CSS 1 became a W 3 C Recommendation 17 December 1996. CSS 2 � CSS 2 became a W 3 C Recommendation 11 January 1999. � CSS 2 has added support for media (printers and aural devices), downloadable fonts, elementpositioning and tables.
CSS Versions CSS 3 � CSS 3 is about breaking CSS into smaller modules.
W 3 C CSS Specifications and Timeline Specification CSS 1 (Revised) CSS 2. 1 CSS Mobile Profile 2. 0 CSS TV Profile 1. 0 CSS Print Profile Draft/Proposa Recommendatio l n 17. Dec 1996 11. Apr 2008 12. May 1998 08. Sep 2009 10. Dec 2008 14. May 2003 13. Oct 2006
W 3 C CSS Specifications and Timeline Specification CSS 3 Namespace CSS 3 User Interface CSS 3 Selectors CSS 3 Fonts CSS 3 Colors CSS 3 TV CSS 3 Backgrounds and borders Draft/Proposa Recommendatio l n 23. May 2001 23. May 2008 11. May 2004 10. Mar 2009 18. Jun 2009 21. Jul 2008 14. May 2003 10. Sep 2008
W 3 C CSS Specifications and Timeline Specification Draft/Proposa Recommendatio l n CSS 3 Text CSS 3 Lists CSS 3 Line CSS 3 Box model CSS 3 Multi column CSS 3 Ruby CSS 3 Speech 06. Mar 2007 07. Nov 2002 15. May 2002 09. Aug 2007 30. Jun 2009 14. May 2003 16. Dec 2004
W 3 C XML Specifications and Timeline Specification Draft/Proposa Recommendatio l n CSS 3 Paged Media (PM) CSS 3 Generated PM CSS 3 Print CSS 3 Values CSS 3 Cascade CSS 3 Template Layout CSS 3 Media Queries 10. Oct 2006 04. May 2007 13. Oct 2006 19. Sep 2006 15. Dec 2005 02. Apr 2009 15. Sep 2009
W 3 C DOM Activities � The Document Object Model (DOM) is a platform and language neutral Application Programming Interface (API) that allows programs to access and update the content, structure, and style of a document.
Other W 3 C Activities The Web Accessibility Initiative (WAI) � WAI define guidelines for how to make Web content accessible to people with disabilities. � WAI is working for "Web accessibility for all" through technology, guidelines, tools, education, research and development projects.
The Future of the Web � The future of Web design lies within three technologies: ◦ HTML 5 ◦ Cascading Style Sheets (CSS) ◦ Java. Script � These technologies used together provide Web pages that easily adapt to smartphones, tablets, gaming devices and smart TVs, as well as to traditional PCs
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