2.3.1 Three Flashes or Below Threshold Level A

Web pages do not contain anything that flashes more than three times in any one second period, or the flash is below the general flash and red flash thresholds.

*Since any content that does not meet this success criterion can interfere with a user’s ability to use the whole page, all content on the Web page (whether it is used to meet other success criteria or not) must meet this success criterion. See Conformance Requirement 5: Non-Interference.

[View on W3C.org]

Testing & Remediation

How to test: Navigate to any page that contains flashing content. While the content flashes, say "A and B and C". This generally equals 3 vocalizations per second. If the content flashes faster that you saying "A and B and C", this success criterion will fail. You can also use a tool to help test this, such as the PEAT (Photosensitive Epilepsy Analysis Tool). It is Windows only but can be installed on a dual-boot Mac. How to remediate: Depending on the type of content and the frequency of which it flashes will determine how to remediate issues related to this Success Criterion. You may need to edit the content that flashes so it doesn't flash more than 3 times per second or you could completely remove the content.

Questions and Answers

Are animated gifs okay to have?

If I have a gif on a site that loops continuously. Is that okay or does it violated the 'can't have repeating flashing stuff' rule?