Best Practice 2.12 – Provide three flashes or below threshold (Advanced level)

Ensure all flashing items are dimmed, and cover only a small area of the screen or the flashing rate is three times per second or less. Otherwise, this may cause problems for persons who suffer from epilepsy.

Before Rectification In this example, the banner is programmed so that it will flash and update to a new content frequently. The flash is very fast and bright. This flashing content can cause seizures for people who are suffering from epilepsy.

After Rectification It is better to replace the flashing content with static content, or ensure the flashing object only take up a very small portion of the page and the flashing rate is less than three times per second.

W3C WCAG Reference: 2.3.1 Three Flashes or Below Threshold