Technologies have been developed to make personal computers accessible to people with disabilities, important for promoting inclusion in everyday life, education, and work. In the 90s, the spread of Internet applications, and specifically of the Web, created a new issue: Would the Web be accessible to people with disabilities? Web accessibility is partially dependent on assistive technologies used by people with disabilities to access their PCs. But, it also depends on whether people with various disabilities can perform specific tasks on their PCs with the help of their assistive technologies. Another dimension of Web accessibility is the responsibility of Web authors, developers, designers, and technologies they use to develop Web content.
Key Terms in this Chapter
Device Independence: The most common computer “input devices” are the keyboard and mouse. In most cases, device independence means a function or feature can be accessed by some means other than using a mouse, though ultimately it means they can be accessed by any device. The phrase implies that Web content will be accessible to anyone, including people with disabilities that frequently use non-conventional devices and access methods.
Text Equivalents: This expression indicates textbased information used to communicate meaning contained in visual (images, video, and animations) or audio media. Text equivalents include text transcript of audio information, synchronous captioning of speech, as well as text descriptions of images, charts, graphics, and videos.
Assistive Technologies: Assistive, adaptive, and rehabilitative devices and technologies that promote independence for people with disabilities by enabling them to perform tasks that otherwise they are unable to achieve, or may have difficulty accomplishing.
Markup Language: A formal language that describes a document by combining text with information about the structure and presentation of the text, and about the relationships between documents. The most widely-known markup language is HTML (hypertext markup language) used to format Web content.
Usability: According to an ISO (ISO, 1998) definition, this term indicates “the extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency, and satisfaction in a specified context of use.” More generally, “usability” denotes the ease with which people can employ a particular tool or object in order to achieve a particular goal. The term also refers to techniques for testing ease-of-use of existing products as well as methods for improving simplicity of usage during the design process of new ones.
Style Sheet: A “style sheet” is a mechanism (supported by desktop publishing programs) used to apply display formatting to text, separating the presentation from content. Custom style sheets can be created by individuals that may include a wide variety of formatting properties that dictate how particular documents are displayed. The use of style sheets in Web documents is based on the CSS (cascading style sheet) language, used to apply formatting to (X)HTML Web pages.
Digital Divide: This expression denotes the socioeconomic differences between communities or groups and their ability to access information technology. A digital divide is created when network infrastructure, computing technology, or computer literacy is lacking. At one end of the divide are those “with” technology: They advance and grow. At the other end of the divide are those “without” technology: They stagnate and fall behind those who have access to technology.