2.3.2 Three Flashes

Who it helps

People with photosensitive seizure disorders are protected even from small flashing areas, which can still trigger seizures in some people. People who view content up close or on large screens also benefit, since a small flash can fill more of their field of view.

How to meet it

• Remove flashing content, or slow it to three flashes or fewer in any one second.
• Check small elements too, such as blinking icons, cursors made of images, and animated badges.
• Prefer gentle fades or a single color change over on-and-off blinking.
• Run videos and animated GIFs through a flash analysis tool, and check every one-second window.
• Level AAA is not required by most laws or policies, which point to AA. It is still worth meeting where you can.

Examples

.badge-dot {
  width: 12px;
  height: 12px;
  background: #b00020;
  animation: blink 0.2s steps(1, end) infinite;
}
@keyframes blink {
  50% { background: #fff; }
}

.badge-dot {
  width: 12px;
  height: 12px;
  background: #b00020;
  animation: fade 2s ease-in-out infinite;
}
@keyframes fade {
  50% { opacity: 0.5; }
}

Common mistakes

• Assuming a small flashing element is fine because it passes 2.3.1; at AAA, size does not matter.
• Using fast blinking for status lights, recording indicators or new-message badges.
• Forgetting animated GIFs and stickers that users post in comments or chat.
• Counting flashes over a whole clip instead of checking each one-second period.

Related criteria

• 2.3.1 Three Flashes or Below Threshold
• 2.3.3 Animation from Interactions
• 2.2.2 Pause, Stop, Hide

Official W3C explanation of 2.3.2