W3C / WAI

The W3C is an independent international organization that determines the protocols and standards for the Web. W3C creates the HTML, CSS, etc.. One of the first initiatives of the W3C was to develop accessibility standards. This is the objective of WAI . The working groups of WAI accessibility standards developed especially for web browsers, tools for managing Web content, assessment tools and web content. Standards (Recommendations) developed by the task force working on the WAI web content are called the Web Content Accessibility Guidelines (WCAG).

WCAG 1.0

Version 1.0 of the recommendations of Web Content Accessibility Guidelines ( WCAG 1.0 ) was an important step to make the Internet more accessible to people with disabilities. Finalized in 1999, WCAG 1.0 is organized into 14 recommendations, themselves containing multiple control points that can be used to determine the accessibility of a web page. They are classified into 3 priority levels or levels of compliance. Priority 1 (or level A compliance) was a basic requirement for some groups of people can use Web documents. Priority 2 (AA or level of compliance) showed greater accessibility and the removal of significant barriers to access to content. Priority 3 (or level AAA compliance) achieved a better Web Content Accessibility Guidelines. WCAG 1.0 were highly related to HTML. They were also the first resource from which the recommendations of Section 508 have been written.

Over time, the WCAG 1.0 began to be exceeded. As Web technologies and technologies for people with disabilities progressed, compliance became more difficult to obtain because some checkpoints became less and less adapted and more difficult to verify. The development of WCAG 2.0 then began.

WCAG 2.0

The WCAG 2.0 (see also the French version of WCAG 2.0 ) is based on the fundamentals of WCAG 1.0 but also introduces significant changes that we explain here. On a practical level, some developments in WCAG 2.0 are subtle. On the one hand, some things do not change as for example, form fields still need labels, data tables must always have headers and images still need a text alternative. Web developers create accessible Web sites will not have to change many habits. On the other hand, WCAG 2.0 represents a substantial evolution of the philosophy of the WCAG. The main changes are the recommendations that focus on principles and more about techniques. This allows recommendations to be no longer dependent on technological change and thus to remain true. Moreover, they are designed so that compliance can be verified reliably. Although the actual measurement of compliance may be difficult, the recommendations are structured to reduce the interpretation of such compliance.

The passage of recommendations based on technical recommendations based on principles also reduced the number of concepts called first-level principles. WCAG 1.0 had 14 top-level principles. WCAG 2.0 has only four top-level principles, each with a list of success criteria. These four principles can each be designated by one word:

• Perceptible
• Usable
• Understandable
• Robust

These principles are discussed in detail in the document Developing a Web site accessible (FOR) .