Success Criterion 2.3.1
Conformance level A

Content Flashing Faster Than 3 Times per Second

2.3.1 — Three Flashes or Below Threshold

Scenario

Setting

An email client's compose window

What’s wrong

No numbered W3C failure technique exists for this rule — it fails simply when the required feature/behavior is missing or inadequate (see the scenarios below).

Example

Picture an email client's compose window: no numbered W3C failure technique exists for this rule — it fails simply when the required feature/behavior is missing or inadequate (see the scenarios below).

Why it matters

People with photosensitive epilepsy and others sensitive to rapid flashing. In this case (an email client's compose window), they are interrupted before they can finish reading.

How to test

Run the content through the Photosensitive Epilepsy Analysis Tool (PEAT): confirm no flash exceeds 3 times per second within any one-second window.

How to fix

Nothing may flash more than 3 times per second above the general or red-flash thresholds.

Outcome

Once corrected, an email client's compose window lets them finish the task at their own pace.

Who is affected

People with photosensitive epilepsy and others sensitive to rapid flashing.

Learn more

Understanding Understanding document (opens in a new tab)