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Blinking Page Elements and Marquees
ISSUE:
Blinking page elements and marquees (text or images that scroll on the screen) can be problematic for persons using screen-readers, screen magnification applications, users with cognitive impairments or users of some hand-held devices. Blinking page elements or the refreshing of the screen to animate a marquee may trigger a seizure in people with photosensitive epilepsy (see Screen Refresh). In order to minimize the probability of inducing an epileptic seizure, screen elements that flicker or change should do so at a frequency of less than twice a second (2 Hz) or greater than 55 times a second (55 Hz).
STANDARD:
- Avoid the use of blinking page elements and scrolling marquees.
- Blinking page elements and the refreshing of the screen to animate marquees shall do so at a frequency of less than twice a second (2 Hz) or greater than 55 times a second (55 Hz).
