Reading order and tabbing are important considerations
for making accessible Flash websites.
When you design an interface, the order that it appears on the page
might not match the order in which the screen reader describes each
instance. You can control and test reading order, as well as control tabbing
in the SWF file.
Controlling reading order
The default
reading order is not predictable and does not always match the placement
of your assets or the visual layout of the page. Keeping the layout simple
can help create a logical reading order without using ActionScript. However,
you have more control over reading order if you use ActionScript
and test the reading order in your SWF files.
Important: Do not miss ordering a single instance in
your SWF file, or the reading order reverts to the default (and
unpredictable) reading order.
Controlling tabbing and content
Visitors
who rely on screen readers to describe a site’s content typically
use tabbing and keyboard controls to navigate the operating system
and web pages, because using the mouse is not useful when the screen
cannot be seen. Use the
tabIndex and
tabEnabled properties
with the movie clip, button, text field, or component instances
to offer intelligent tabbing control in accessible SWF files. In
addition to tabbing, you can use any key-press actions to navigate
through the SWF file, but you must communicate that information
using the Accessibility panel. Use the
Key class
in ActionScript to add key-press scripts to the SWF file. Select
the object for which you want to use the key-press script, and add
the shortcut key in the Shortcut field on the Accessibility panel.
Add keyboard shortcuts to essential and frequently used buttons
in your SWF file.
Note: In ActionScript 3.0, tabIndex and tabEnabled are
properties of the InteractiveObject class. In ActionScript
2.0, they do not require a class reference.
Note: Avoid
invisible buttons in accessible SWF files, because screen readers
do not recognize these buttons. (Invisible buttons are buttons for
which you define only a hit area, the clickable region, for the
button.)
Many SWF files have a rapid succession of information,
and screen readers frequently cannot keep up with this pace. Provide
controls for the SWF file, letting the user use buttons to navigate
through the file at their own pace, and letting them pause the process
if necessary.
