Understanding how assistive technologies handle animation
When a screen reader encounters content created with Animate CC, it loads the current state of the movie and notifies the user. With the Window-Eyes screen reader, the user hears, "Loading…load done." Once a piece of content has been read, the screen reader moves on to read other parts of the content and the rest of the page.
A unique feature of content created with Animate CC is that it may change over time. As the content changes, Adobe Flash Player 11 software sends a signal to the screen reader notifying it that there has been a change. When the screen reader receives this notification, it automatically returns to the top of the page and begins reading it again.
The following example illustrates the serious implications of content created without consideration for users of screen readers. A poorly designed banner ad placed at the top of the page might loop constantly through a few frames. When Flash Player encounters this banner, it will send repeated notifications to the screen reader of changes in the content, and the screen reader will continually return to the top of the page. This problem can seriously erode the experience for screen reader users.
To address this specific issue, Adobe worked with GW Micro to create a Halt Flash Events keystroke (Alt+Shift+M) for the Window-Eyes screen reader. This keystroke allows a screen reader user to suspend Flash notifications on the page. Pressing the keystroke again allows the user to resume Flash notifications.