Nothing on a webpage flashes more than three times in a second.
The terms “flashing” and “blinking” can mean the same thing. WCAG distinguishes flashing as content that can cause a seizure. Blinking refers to content that can be a distraction. The two can be the same if blinking occurs faster than three times per second.
What to do?
- Limit or eliminate any flashing content
Resources
Plain English Explanation
2.3.1 is written to prevent seizures.
The point here is to severely restrict flashing content.
Although there are exceptions that provide for automatic content, I recommend making your website as static as possible by default, with options to activate helpful automatic content.