Abstract
The development of the Internet has changed a purely text-based environment with relatively simple presentation features to one driven by graphics and multimedia (including complex scripting). This development has presented many difficulties for those computer users with disabilities ranging from congenital causes, aging, or injury. Web accessibility is related to usability, or the design of Web pages that can be used by as many computer users as possible, and Web accessibility refers to designing a Web page “so that more people can use...[a] web site effectively in more situations” (Thatcher et al., 2002, p. 13). “... The objective is to make the world directly usable by as many people (with and without disabilities) as possible.” (Vanderheiden, 2003).
TopIntroduction
The development of the Internet has changed a purely text-based environment with relatively simple presentation features to one driven by graphics and multimedia (including complex scripting). This development has presented many difficulties for those computer users with disabilities ranging from congenital causes, aging, or injury. Web accessibility is related to usability, or the design of Web pages that can be used by as many computer users as possible, and Web accessibility refers to designing a Web page “so that more people can use...[a] web site effectively in more situations” (Thatcher et al., 2002, p. 13). “... The objective is to make the world directly usable by as many people (with and without disabilities) as possible.” (Vanderheiden, 2003).
Web accessibility is an issue that affects computer users everywhere and is the degree to which a given Web site is accessible by all users. Tim Berners-Lee, inventor of the World Wide Web stated: “The power of the Web is in its universality. Access by everyone regardless of disability is an essential aspect” (W3C WAI - http://www.w3.org/TR/WCAG10/):
Provide appropriate alternative text...; provide headings for data tables...; ensure users can complete and submit all forms...; ensure links make sense out of context...; caption and/or provide transcripts for media...; ensure accessibility of non-HTML content, including PDF files, Microsoft Word documents, PowerPoint presentations and Adobe Flash content...; allow users to skip repetitive elements on the page...; do not rely on color alone to convey meaning...; make sure content is clearly written and easy to read...; make JavaScript accessible...; design to standards....(fromWebAIM (2008), “Principles of accessible design”)
The second version, WCAG 2.0 (still in development), uses a four-principle approach in presenting guidelines (W3C-WCAG2.0 - http://www.w3.org/TR/WCAG20/):
• Perceivable: Available to the senses (vision and hearing primarily) either through the browser or through assistive technologies (e.g. screen readers, screen enlargers, etc.)
• Operable: Users can interact with all controls and interactive elements using either the mouse, keyboard, or an assistive device.
• Understandable: Content is clear and limits confusion and ambiguity.
• Robust: A wide range of technologies (including old and new user agents and assistive technologies) can access the content (from WebAim, “Focusing on Web Accessibility”)
Key Terms in this Chapter
Zoom Text: A computer application that magnifies text, adjusts background and font colors, and provides speech for the user.
CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart): “a program that protects websites against bots by generating and grading tests that humans can pass but current computer programs cannot” - (http://www.captcha.net/)
JAWS (Job Access With Speech): A screen reader.
Hypertext Markup Language (HTML), Extensible Markup Language (XML): The presentation code that makes up a Web page.
Screen Reader: (such as JAWS): An assistive technology device that interprets computer code and reads to the user (see JAWS).
Code: The Hypertext markup language and other scripting that underlies a Web page
CSS: Cascading Style Sheets, a feature of Hypertext Markup Language (HTML) that enables Web designers and users to control the display of a Web page, using style sheets.
Web Accessibility: A term describing the degree to which a Web page can be accessed by the user, especially a user with disabilities.
Barriers: Obstacles to access of information from a Web page, or from computer-generated information - these include the incompatibilities of the code of the Web page with assistive technology.