Movement, Parallax, and Flashing Content

Overview

Content should not move or change unexpectedly or automatically, and movement should be under the control of users. This includes features like parallax effects, autoplaying videos, auto-advancing carousels, auto-updating content, and flashing content. In addition to creating distractions for many people, these effects can cause seizures, migraines, nausea, and dizziness.

Guidelines

  • Avoid parallax scrolling and motion effects. Parallax scrolling and motion effects can cause direct physical harm (dizziness, nausea, migraines, etc.) for people who have vertigo, vestibular disorders, migraine sensitivity, cognitive impairments, visual processing issues, and some people who are neurodivergent. If any motion or parallax effects are present, give users the ability to determine whether they are active (e.g., have a toggle on the page to allow users to turn parallax effects on).
  • Avoid auto-playing videos or animations, auto-advancing carousels or slideshows, and auto-updating content. If content that automatically plays or updates is present, it must have controls that allow users to pause, stop, or hide it.
  • Ensure that videos, animations, and other content doesn't flash rapidly. Rapid flashing (typically defined as more than three times per second), can induce seizures in people with photosensitive epilepsy, and can also cause dizziness, migraines, and nausea. If linking to third-party content that includes flashing is unavoidable, provide a clear written warning about the content and danger, do not embed the content, ensure that the content does not autoplay, and be prepared to provide accessible alternatives or accommodations.
  • Avoid background videos or animations, and treat them like any other video content - they must have controls to pause, stop, or hide them.

How to Test

  • Manually review to ensure that no parallax or motion effects are present.
  • Manually review to ensure that there are no autoplaying videos or animations, auto-advancing carousels, or auto-updating content, and that if any are present, that there are obvious controls to pause, stop, or hide them. Verify that controls can be activated with a keyboard, mouse, and touchscreen.
  • Confirm that no content flashes rapidly. Confirm that essential links to third-party flashing content provide a clear warning. 

Additional Resources