Accessible Websites

What does accessible Internet mean?

An accessible website is a website which can be used without difficulties. Hard- or Software should not be a barrier between information and user. The kind of disablement a person has estimates the grade of difficulty he may have using the Internet. Visually impaired students usually have difficulties using the Internet because additional Software (Screenreader) is necessary and often not available. The Screenreader converts written letters in Braille letters, read the texts or enlarge the letters to such an extend that visually impaired students can read them. At this stage Screenreaders cannot reproduce the layout of screens.

We would like to make it clear that these barriers can be removed easier than you think. To offer accessible Internet to handicapped persons you need not change the programming, you need not do without modern design, it is the quality of the programming that is important.

When it is possible read and use the text of a website after the graphics have been removed, then it is possible to make use of a Screenreader, and so make information accessible to handicapped persons.

 

 

Principles for web-design

The Web Accessibility Initiative (WAI) of the World- Wide- Web Konsortium (W3C) has guidelines for the construction of accessible websites. guidelines. We request all computer scientists to make use of the W3C- Technologies. Should the guidelines not be followed for some reason alternatives should be offered. To ensure accessibility there are two possibilities:

  • Apart from the normal version a "text-only" version is offered. The text-only version does not include graphics
  • One single version for all user, by making use of this version you must be prepared to do without some graphic elements.

Important guidelines:

  • Separation of contents and layout: By making use of cascading style sheets (CSS) the layout can be designed separately from the contents. This means the user can make use of his own layout.
  • Alternatives to visual or audible contents, with the same function as the original form
  • Text formatting: Letters must be big enough and easy to read. The font size of a word should stay the same as far as possible because different font sizes in one word cannot be converted by the Screenreader.
  • Colours should compose contrast, these are easier for the visually impaired to see. (think of backgrounds as well...) If possible refrain from using too many colours in a graph or a picture. Graphs must be constructed plain and simple. Screenreaders cannot convert graphs, therefor it is sensible to add an alternative text in HTML-Quellcode which can be translated. All graphs must be accompanied by an explanation. Frames should be accompanied by a non-frame version, enabling access for handicapped persons.
  • Tables cannot be translated by the Screenreader,use them sparingly, and always add an explanation. Important: Do not make use of tables for data if another possibility exists!
  • For Scripts, Applets and Plug-Ins. alternative texts must be available should the original data not be convertible by the Screenreader.
  • You need not do without Java script. You may make use of it if you make use of Noscript-Tags to create alternative possibilities. Java script cannot be interpreted by browser working with MS-DOS, neither by the text browser often used by the blind - "Lynx".
  • Links: The usage of Links must be easy and clear. Panels make this possible and are easier for the handicapped to use. Texts following after links must be clear and understandable, even without knowledge of the original context.
  • PDF- Data: One should keep in mind that texts must be readable for the Screenreader. Avoid too large texts, either keep them small or divide a large text into smaller ones.

Links:

Responsible: Dr. Uwe Grebe - Last Modified: 9. August 2011