2.3.1 - Three flashes or below threshold

The intent of this success criterion is to allow users to access the full content of a site without inducing seizures due to photosensitivity. Individuals who have photosensitive seizure disorders can have a seizure triggered by content that flashes at certain frequencies for more than a few flashes.

Ways to meet the criterion

Do not design content in a way that is known to cause seizures in people with photosensitivity. Ensure web pages do not contain anything that flashes:

  • more than 3 times / second
  • minimize the following aspects of the flashing object:
    • colour contrast of flashing images
    • speed of flashes
    • amount of red colour in the images

As a general rule, none of the web content should be flashing.

Supported general and HTML techniques to meet the criterion: