Accessibility and Dreamweaver MX 2004 - Assistive Technologies
(Page 4 of 11 )
Users with disabilities frequently rely on specialized hardware and software tools to access web content. These tools, known as assistive technologies, range from screen readers to touch screens and head pointers.
Blind users frequently use software called a screen reader that reads the contents of a web page out loud. Two common (and previously mentioned) screen readers are JAWS, from Freedom Scientific, and Window-Eyes, from GW Micro. Screen readers enable users to hear, rather than view, the contents of a web page; however, a screen reader can read only text, not images or animations. It is essential, therefore, that images and animations be assigned text descriptions that screen readers can read. These text descriptions are called alternative text, or alt text.
Users with impaired mobility may rely on the keyboard instead of the mouse to navigate web pages. In Internet Explorer, pressing Tab moves the focus of the browser among all available links on a page. The border around links in IE lets the user know where the current focus of the browser is positioned. Pressing Enter activates links, giving the same effect as clicking a mouse button. In Figure 3-1, notice the border around the link for the Apress TechZone logo.
Assistive devices include a touch screen, which allows an individual to navigate the page using her or his hands without requiring the fine-motor control needed to use the mouse, and a head pointer, which is simply a stick placed in a person’s mouth or mounted on a head strap that the person uses to interact with a keyboard or a touch screen.
Figure 3-1. Note the border indicating the current focus.
In these cases, it is very important that essential components of the page work without a mouse. Rollovers, drop-down menus, and interactive simulations are all examples of elements that typically depend on the mouse for user interaction. The designer or developer of these elements must ensure that keyboard-defined events are included with mouse-defined events. A quick test using the keystrokes available in IE can provide a valuable glimpse of the difficulties a web page may present for users with disabilities who cannot use a mouse. For example, a user can move to any focusable object, including links, form controls, and embedded objects, by pressing the Tab key; pressing the Enter key will activate selected links. Pressing Ctrl+Tab moves between frames. This replicates some of the ways users who cannot use a mouse must interact with a web page.
 This chapter is from ASP Web Development with Macromedia Dreamweaver MX 2004, by Rachel Andrew et al., (Apress, 2004, ISBN: 1590593499). Check it out at your favorite bookstore today.
Buy this book now. |
Next: Accessibility Standards >>
More Design Usability Articles
More By Apress Publishing
/ 11 
