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Accessibility of services on the web. Table of contents. Statistics Definitions Different kinds of disabilities Solutions for accessibility. Statistics. 21.1% of people with vision problems have Internet access 27.2% of people with hearing problems
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Table of contents • Statistics • Definitions • Different kinds of disabilities • Solutions for accessibility
Statistics • 21.1% of people with vision problems have Internet access • 27.2% of people with hearing problems • 22.5% of people with difficulty using hands • 42.2% of people with a learning disability => 56.7% of non-disabled people have Internet access Survey realised in the USA in 2001
Definition • Disability: ”Disability is a physical or mental impairment which has an effect on the ability to carry out normal day-to-day activities” • Accessibility: ”Accessibility functionality makes content resources usable by persons with disabilities” • Web accessibility: ”Web accessibility refers to the practice of making websites usable by people of all abilities and disabilities”
Different kinds of disabilities • Visual (blindness, poor eyesight and colour blindness) • Aural (deafness and impaired hearing) • Cognitive (dementia and dyslexia) • Physical or Motor (muscular dystrophy, cerebral palsy)
W3C • W3C (World Wide Web Consortium) • Founded in 1994 by Tim Berners-Lee • Objective: development of web standards and guidelines. • Examples: CSS, HTML, XHTML, SOAP, XML, XForms
WAI • WAI (Web Accessibility Initiative) • Has been launched by W3C in 1997 • Objective: creation of international standards and guidelines in order to improve the accessibility of web for people with disabilities
Tools for blind people • Screenreader • Text-to-spreech • Braille output device • Oralux: Linux distribution
Solutions for visual disability • Use CSS • Use headings (H1, H2, H3, H4) • All informational images use ALT text • Provide a site map • Make sure that the text can be resized • Efficient contrast between background and foreground colours
Solutions for aural disability • For any audio content => Provide subtitles or written transcripts
Solutions for cognitive disability • Use simple and easy language (non technical) • Avoid using words in their non-literal sense • Avoid using abstractions • Use large headings • Do not use scrolling text
Solutions for physical or motor disability • These users do not use mouse but only keyboard • Use vertical navigation links • Avoid flickering between 2 and 55 Hz (epileptic users)
Conclusion/Interpretation • Solutions are generally easy to implement • Solutions are generally cheap • Solutions are usefull for disabled and also valid users