Web Content Accessibility Guidelines

The Web Content Accessibility Guidelines ( WCAG short, . Eng " accessibility guidelines for Web content " ) are recommendations of the Web Accessibility Initiative ( WAI) of the World Wide Web Consortium (W3C ) for barrier-free design of the content of Internet sites. Web pages that meet these guidelines are also accessible for people with sensory and motor ( mental and to a certain extent ) constraints, that is, they can capture the information provided and make necessary inputs. The WCAG are at the center of numerous guidelines and specifications, which drew up the WAI to promote a barrier-free Internet. In Germany, the practical implementation of these policies is still in its infancy and has been funded since 2002 by the legal establishment in the barrier - free Information Technology Ordinance ( BITV).

The old version of WCAG 1.0 had since May 1999 recommendation status. The latest version of WCAG 2.0 was adopted after more than nine years of consulting on December 11, 2008. Today, one has authorized German translation.

Background

WAI develops guidelines for barrier-free design of the Internet. The activity is not focused on the contents of the websites alone. Likewise, there are recommendations for authoring tools and user agents (browsers, media players and other assistive technologies). Also counts for activity with comprehensive information on accessible Internet.

With the increasing popularity of the World Wide Web ( WWW) in the 90s, and thus the distribution graphically illustrated websites, the problem became acute that the information the websites for people with disabilities were no longer accessible. This at first sight bizarre -looking development - the increasing exclusion of these people at the same time easier to use for others - for several reasons. In the 80s, the character and line-based representation of the user interfaces of operating systems such as MS- DOS, Unix, CP / M was easily accessible for deaf, blind or similar disabilities, since the linear structure of the representation in text-based terminal program, or the waiver of represent acoustic outputs no barriers for braille and other assistive technologies. Disabled and non-disabled people were able to freely communicate. Graphically -oriented representations of the system surfaces represent in itself does not constitute a barrier for people whose visual capabilities are limited or a mouse can not operate. For example, support modern versions of the Windows operating system including the use of the keys. The problems lie mainly in the lack of application of existing standards. The following reasons also play a role:

• The high complexity of web design: many different technologies complicate the creation of web offers that are easily accessible in general.
• Lack of standards compliance browser
• Lack of awareness of the problem at web designers
• The operation is not possible regardless of the device used: however, control and input with mouse, keyboard and other input devices must be possible.

Some examples of problematic web design:

• Before CSS was widely supported, HTML tables were a preferred means for designing the layout. The planar structure produced thereby can not be properly reproduced by Braille displays or screen readers, since the representation often does not reflect the actual context of the data.
• Hyperlinks whose descriptive text contains no reference to the target ( eg, a link with the text " here " ), are also difficult to measure for the visually impaired.

In principle provides accessibility is not a high overhead and is only one aspect of a comprehensive usability of computer technologies. Provided, however, that the additional requirements from the outset be involved in the planning processes, because subsequent changes are often too complex. Also means Accessibility does not mean abandoning good design. Pure HTML pages are not in principle accessible and even multimedia content to promote accessibility for certain types of disabilities. For example, a poor reader from birth deaf often because the font is derived from the spoken language, which they have a difficult or impossible. Illustrative images can then advance the understanding of the text that should additionally be kept simple.

Similar problems also occur in other areas of computer-based work. For example, the work as a programmer for blind people is increasingly difficult as with the proliferation of graphic -oriented notations of software models in the form of UML, etc., the inaccessibility of UML diagrams acting exclusively for the blind.

Impact of WCAG

Although the recommendations of the W3C have no legal validity with respect to the development of the Internet, they are nevertheless of great liability for development. It is generally expected of software compliance with the W3C standards. This relates primarily to the browser, which are the main interface to the Internet. The reason for this is partly in the impartial work and the open and discursive development of the standards of the W3C. Add to that the WCAG have already been adopted in the legislation of individual states. The U.S. government had a very early stage signaled support for the guidelines. For example, the German Federal Government has made for all of the federal Internet sites using the BITV the WCAG 1.0 legally binding. Individual states take over the gradually also for the country level. Roughly speaking, has thus received a recommendation from the W3C for the first time as a regulation legally valid status.

Although the valid hypertext standards of the World Wide Web (HTML, XHTML) offer the opportunity to make websites accessible to additional claims were never fully utilized, so that it became clear that independent accessibility guidelines are necessary. In fact, the WCAG have success if still can not be spoken of a general accessibility of the Internet. Numerous international and national initiatives to support these recommendations. For example, the action man annually awards the BEE award for particularly successful accessible internet deals in different categories. The winners are also demonstrations of a successful web design.

News

The WCAG 2.0 have received 2008 Recommendation status on 11 December. Unlike WCAG 1.0, they no longer focus on HTML and CSS as the most important Internet standards, but to describe general, such as layouts, interactions among others must be designed so that the offer is barrier-free. The implementation of these guidelines for individual technologies such as HTML, Java, Flash, or PDF is coordinated by the responsible institutions or companies. This WCAG remain open to the rapid technological developments of the Internet and new technologies can be integrated.

The recommendations in detail

The individual to be tested points of WCAG 1.0 are divided into 14 groups and have three different priorities (A, AA, AAA). The WAI provides around the WCAG numerous supportive services in order to facilitate the reactions of the guidelines. The main points are summarized below:

• Clear structure of the document with headings and lists, the layout is done wherever possible with CSS
• The purpose or function of images and animations is described by alt attribute
• To multimedia offerings exist textual alternatives, subtitles and audio description and transcription of audio for video
• Diagrams are described in the text or by using the attribute longdesc
• Frames have meaningful name attributes and the noframes element is used
• Tables are possible line -line reading sensible. Its content is described and summarized.
• Use user-side image maps
• Scripts, applets, etc. are accessible or there are accessible alternatives
• Tables are only used for the presentation of data.

It is also important to check the pages on conformity - so-called validation. This also appropriate software tools can be used at least partially. However, not can be checked automates all aspects of conformity.

In principle, the use of other technologies is not excluded if certain principles are adhered to. For example, can certainly be HTML, CSS and JavaScript to use if all the information is represented by HTML, CSS layout controls and the use of JavaScript to improve the usability is limited. If the display of information but integrated so that the functionality of JavaScript, Java, Flash, CSS is imperative, etc., the offer is not wheelchair accessible. Many of the expanding technologies provide independent functionalities to improve accessibility (Java, Flash), which is often not used or not supported by assistive technology.