This technique relates to Success Criterion 2.2.2: Pause, Stop, Hide (Sufficient).
The objective of this technique is to ensure that blinking content can be turned off using user agent features. User agents allow users to stop animation of content in certain technologies. When the user activates this feature, all animation, including blinking, is stopped. This feature can be provided either through interactive controls that conform to WCAG or through documented keyboard shortcuts.
The most common way for users to stop animation is to press the "escape" key. As long as there are no processes that take precedence in the event queue for a press of that key, this is taken as a command to stop animation of moving or blinking content.
Technologies for which this is known generally to work include:
- Graphics Interchange Format (GIF)
- Animated Portable Network Graphics (APNG)
- A page contains a blinking banner intended to draw the user's attention to it. The banner is an animated gif image which repeats indefinitely. The user presses the "escape" key, which causes the user agent to stop the animation of all animated gif images on the page.
- Load a page that includes blinking content.
- Activate the browser's stop animation command (usually the Escape key).
- Check to see if the blinking stops.
- Check #3 is true.