Avoid causing the screen to flicker |
Section 508 1194.22(j); WAI / WCAG 1.0 checkpoint 7.1
Issue Description The page contains a graphic object that may cause the screen to flicker. Make sure the page does not contain an animated object with a refresh rate of between 2 to 55 frames per second.
How to check Make sure no animated object has a refresh rate of between 2 to 55 frames per second. In other words, make sure no image repeatedly flashes or changes from dark to light from 2 and 55 times per second. If you need to use the animated object, increase its refresh rate to more than 55 frames per second or change its colors to reduce the flickering effect.
Issue Explanation A flickering or flashing screen may cause seizures in users with photosensitive epilepsy. As a result, content developers should avoid causing the screen to flicker. Seizures can be triggered by a light flickering or flashing 2 to 55 times per second, with a peak sensitivity at 20 flashes per second with quick changes from dark to light. Here are HTML elements that may cause flickering: SCRIPT: A scripting language can be used to create animations OBJECT: An OBJECT can contain movies, animated GIFs, or animated Java applets EMBED: This tag is usually used to include movies on the page APPLET: Java applets can display animations