comp101 2.0

• W3C


  As steward of global Web standards, W3C's mission is to safeguard the openness, accessibility, and freedom of the World Wide Web from a technical perspective
• W3C's primary activity


  To develop protocols and guidelines that ensure long-term growth for the Web
• Tim Berners-Lee wrote a proposal for a system called the World Wide Web


  1989
• Tim Berners-Lee founded the World Wide Web Consortium (W3C) at the Massachusetts Institute of Technology


  1994
• Inria became the first European W3C host


  1995
• Keio University of Japan (Shonan Fujisawa Campus) became the first Asian W3C host


  1996
• ERCIM (European Research Consortium for Informatics and Mathematics) took over the role of European W3C Host from Inria


  2003
• W3C announced Beihang University as the fourth Host


  2013
• Web


  The most popular way of accessing the Internet, other ways are email, and ftp
• The W3C community is passionate about creating free and open Web standards
• HTML


  Describes what's on a page
• HTTP


  Allows the page to be communicated to a user
• The power of the Web is in its universality. Access by everyone regardless of disability is an essential aspect
• Disabilities addressed by Web accessibility

  • Hearing
  • Learning and cognitive
  • Neurological
  • Physical
  • Speech
  • Visual
• Examples of Web accessibility features

  • Captions on audio and multimedia content for people who are hard of hearing
  • Clear and consistent layout for people with learning and cognitive disabilities
  • Keyboard support for people with physical disabilities and who do not use a mouse
  • Text alternatives for people with visual disabilities and who are using screen readers
• Web accessibility benefits people with and without disabilities
• Examples of people who benefit from Web accessibility

  • People with temporary situational limitations, such as a broken arm
  • People using mobile devices, televisions, and other access channels
  • People using older computers, with low bandwidth, and other limitations
  • People who are new to computers, to the Web, or to your own Web site
  • People who are not fluent in the language of your particular Web site
• Page title


  Good page titles are particularly important for orientation — to help people know where they are and move between pages open in their browser. The first thing screen readers say when the user goes to a different Web page is the page title
• Image text alternatives ("alt text")


  Text alternatives ("alt text") are a primary way of making visual information accessible, because they can be rendered through any sensory modality (for example, visual, auditory or tactile) to match the needs of the user
• Internationalization


  Abbreviated to 'i18n' in English, because there are 18 characters between the 'i' and the 'n'
• The" W3C Internationalization Activity" works with W3C working groups and liaises with other organizations to make it possible to use Web technologies with different languages, scripts, and cultures
• Unicode


  A universal character set, i.e.. a standard that defines, in one place, all the characters needed for writing languages in use on computers. It is a superset of all other character sets that have been encoded
• As a content author or developer, you should nowadays always choose the UTF-8 character encoding for your content or data
• Characters


  Represent letters of the alphabet, punctuation, or other symbols
• I18n quick tips


  • Encoding: use the UTF-8 (Unicode) character encoding for content, databases, etc. Always declare the encoding
  • Language: declare the language of documents and indicate internal language changes
  • Navigation: on each page include clearly visible navigation to localized pages or sites, using the target language
  • Escapes: use characters rather than escapes (e.g. á á or á) whenever you can
  • Forms: use UTF-8 on both form and server. Support local formats of names/addresses, times/dates, etc.
  • Localizable styling: use CSS styling for the presentational aspects of your page. So that it's easy to adapt content to suit the typographic needs of the audience, keep a clear separation between styling and semantic content, and don't use 'presentational' markup
  • Images, animations & examples: if your content will be seen by people from diverse cultures, check for translatability and inappropriate cultural bias
• First steps in Web internationalization

  1. Character encoding declaration

  2. Primary language declaration
• ASCII (American Standard Code for Information Interchange)


  ASCII is a character encoding standard that uses 7 bits to represent 128 characters. Originally developed for telegraph communication, it includes characters for the English alphabet (both uppercase and lowercase), digits, punctuation marks, and control characters
• UTF-8 (Unicode Transformation Format 8)


  UTF-8 is a variable-width character encoding that can represent every character in the Unicode character set. It uses 8-bit code units, which allows it to represent the entire Unicode character set while maintaining compatibility with ASCII for characters in the ASCII range. UTF-8 is widely used on the internet and in computing systems
• UTF-16 (Unicode Transformation Format 16)


  UTF-16 is another variable-width character encoding that can represent all Unicode characters. It uses 16-bit code units, allowing it to represent characters outside the Basic Multilingual Plane (BMP) more efficiently than UTF-8. However, it requires more space than UTF-8 for characters in the ASCII range
• UTF-32 (Unicode Transformation Format 32)

  UTF-32 is a fixed-width encoding scheme where each character is represented by a 32-bit code unit. Unlike UTF-8 and UTF-16, which use variable-width encoding, UTF-32 uses a fixed-width format, which means each character takes up the same amount of space (4 bytes). While it provides a straightforward mapping from code points to code units, it can be inefficient in terms of storage compared to UTF-8 and UTF-16 for most texts because it uses more memory
• W3C TOOLS


  • Validator
  • CSS Validator
  • Unicorn
  • Link Checker
  • Cheatsheet
• W3C Validator


  Checks the markup validity of various Web document formats, such as HTML
• CSS Validator


  Checks Cascading Style Sheets (CSS) and (X)HTML documents that use CSS stylesheets
• Unicorn


  W3C's unified validator, which helps people improve the quality of their Web pages by performing a variety of checks. Unicorn gathers the results of the popular HTML and CSS validators, as well as other useful services, such as Internationalization, RSS/Atom feeds and http headers
• W3C Link Checker


  Looks for issues in links, anchors and referenced objects in a Web page, CSS style sheet, or recursively on a whole Web site
• The W3C Cheatsheet


  Provides quick access to useful information from a variety of specifications published by W3C. It aims at giving in a very compact and mobile-friendly format a compilation of useful knowledge extracted from W3C specifications, completed by summaries of guidelines developed at W3C, in particular the WCAG2 accessibility guidelines, the Mobile Web Best Practices, and a number of internationalization tips