Software Standards
Keyboard Accessibility
How would you use a mouse to interact with an application if you couldn’t
see the screen? How about if you couldn’t use your arms? To begin
to understand how the typical AT user interacts with a computer and
software, turn your mouse upside-down. Now you’re left with only
the keyboard for inputting information and navigating an application.
However, most software developers assume the end-user uses a mouse to
navigate elements such as scroll bars, drop-down menus, and graphical
buttons.
According to § 1194.21 (a), AT users must be able to navigate
and interact with an application using only the keyboard. To test for
compliance with this standard is easy: try to use the program as it
was intended using only the keyboard (use the Tab and arrow keys to
navigate). This standard doesn’t forbid the use of graphics or
mouse navigation, but only requires the more basic keyboard navigation
cues to also be present.
Besides, as any “power user” knows, the flexibility to navigate
an application using both the mouse and the keyboard greatly increases
user efficiency.
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Interfering with Other Applications
Users with disabilities—and indeed almost all users—customize
their computers by manipulating the display preferences. For users without
disabilities, this is often done to enhance the visual appeal of the
interface as well as configure the colors and fonts to best suit the
individual’s viewing preferences and needs.
However, for users with disabilities, these settings and/or additional
software can mean the difference between being able to use their computer
or not. For example:
- Someone with low vision uses a high-contrast
setting, the largest fonts available, and occasionally screen magnification
software to maximize use of their vision
- A blind user uses screen reading software
to convert screen text to spoken speech
- A user with hearing loss turns on an
operating system feature that flashes the window title bar to accompany
error and alert sounds
Most applications designed for an operating system follow design standards
that use whatever customized settings a user has. However, to ensure
applications display best for every user, § 1194.21 (b) prevents interfering
with these applications and settings, § 1194.21 (g) requires an application
to incorporate the user's display settings, and § 1194.21 (j) requires
an application to provide several options if it allows users to customize
the interface (e.g., with "skins").
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Screen Text
AT only interprets true textual information. For most applications
designed to work with an operating system, text is sent through the
OS and displayed on the monitor in a standard way. However, some applications
bypass this function. These applications generally end up displaying
text as a graphic. While not apparent to the sighted user, an AT user
may receive little or no information about the text displayed on screen.
To prevent this, § 1194.21 (f) states that text must be displayed
through the operating system.
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Interactive Features
While a visually appealing interface may look easy to use, if you were
to turn off your monitor and flip over your mouse you’d have a
difficult time using some applications. To allow AT to move throughout
an application, § 1194.21 (c) requires an obvious focus marker
that moves around the screen. For instance, if you use a keyboard to
navigate through applications, you’ve probably seen a dotted rectangle
around buttons and fields and watched as it moves with your input.
A related standard, § 1194.21 (l), states that forms must be able
to be understood and completed. This includes being able to move around
the various fields in a logical order and access any text instructions
for filling in the form.
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Graphics
Graphics are used to create enticing interfaces and interactive elements
such as buttons and labels. If the same information isn’t presented
in a textual format, however, non-sighted users won’t be able to
use those features. Therefore, according to § 1194.21 (d), every
graphic element must have textual information about its purpose and
status (e.g., “checked” or “not checked”). Remember,
text contained within a graphic must also have a textual equivalent.
Similarly, § 1194.21 (h) mandates that animations must be accompanied
by non-animated versions of the information.
In addition, many people with disabilities memorize common thematic
elements in order to navigate effectively throughout an application.
Because of this (and to maximize usability), § 1194.21 (e) states
that images must represent the same function throughout an application.
Additionally, § 1194.21 (k) limits the blink rate for text and
graphics. This is to prevent inducing seizures in people with photosensitive
epilepsy.
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Color Usage
§ 1194.21 (i) is designed for users with visual loss as well as
color blindness. It states that color should indicate meaning only after
another means has been used, such as text. Consider what it would mean
to have instructions read “fields in red are required” if
you couldn’t see the color red!
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