Flashing and Motion
Is there any content starting or changing unexpectedly?
Why it’s important
- Jennifer suffers from dizziness, headaches and nausea, often caused by animated scrolling and excessive motion in video.
- Rapata has photosensitive epilepsy. Rapata is affected by flashing lights and contrasting patterns.
Next steps
- Check that the rate of flashing is less than 3Hz (3 times within any one-second period). Avoid fully saturated reds for any flashing content.
- Ensure all flashing items are dimmed, and cover only a small area of the screen.
- Provide a mechanism to suppress any flashing content before it begins.
- Allow users to disable any motion animation triggered by interaction. Advise developer(s) to take advantage of the technique prefers-reduced-motion(this link opens an external website) to prevent animation from being displayed.
- Ensure that no essential information is lost for visitors who choose to disable motion.
- Provide and show controls to pause and/or stop moving or blinking elements that start automatically and last more than 5 seconds in parallel to other content.
References
Resources
- Seizure and Vestibular Disorders (WebAIM)(this link opens an external website)
- Designing Safer Web Animation For Motion Sensitivity(this link opens an external website)
- Video: Using Motion and Web Animation Responsibly(this link opens an external website)