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Strictly no flashing more than 3 times per second (no exceptions).
Why it matters: Provides maximum safety for users with photosensitive epilepsy.
Web pages do not contain anything that flashes more than three times in any one second period.
What This Means: This success criterion is a stricter version of 2.3.1 (Level A). At Level AAA, content must not flash more than 3 times per second with no exceptions, even if the flash is below the general flash threshold. This provides maximum safety for users with photosensitive epilepsy.
Why It's Important: Photosensitive epilepsy can be triggered by flashing content at certain frequencies. At the AAA level, we aim for maximum safety by completely eliminating fast flashing content, regardless of luminance changes. This ensures the highest level of protection for users with photosensitive epilepsy.
Ensure absolutely no content flashes more than 3 times per second. This includes animations, video content, transitions, and any other visual effects. Test all content thoroughly using tools like PEAT (Photosensitive Epilepsy Analysis Tool). Use slower animations, smooth transitions, or static content instead of fast flashing effects.
This criterion ensures that users with epilepsy can access and understand the content, improving their overall experience and ability to use the website effectively.
Impact: When this criterion is properly implemented, it removes barriers for these user groups and creates a more inclusive web experience for everyone.
Content flashes 5 times per second, exceeding the limit.
<div class="flashing" style="animation: flash 0.2s infinite;">
Flashing content
</div>Content flashes at most 3 times per second, meeting the requirement.
<div class="flashing" style="animation: flash 0.4s infinite;">
Slow flashing content
</div>This success criterion benefits the following user groups:
Tip: Use this checklist during development and testing to ensure all requirements for 2.3.2 Three Flashes are met. Check off items as you complete them.
To meet this success criterion, ensure the following requirements are met:
While meeting the minimum requirements ensures compliance, consider these enhancements for a better user experience:
Level AAA is optional, so I don't need to worry about this.
While Level AAA is optional, flashing content can cause serious harm. It's best practice to avoid rapid flashing regardless of compliance level.
Content that flashes exactly 3 times per second, which may still be problematic.
Use slower flash rates (2 per second or less) or eliminate flashing entirely. Consider user safety over technical compliance.
Note: These are official W3C resources for 2.3.2. For the most up-to-date information and detailed technical guidance, always refer to the official W3C documentation.
Implementing 2.3.2 Three Flashes correctly requires understanding your specific context. Code solutions vary significantly based on multiple factors:
HTML, React, Vue, Angular, PHP, Python, and other frameworks each have different patterns and best practices.
Server-side rendering, client-side rendering, static generation, and hybrid approaches require different solutions.
Your existing components, styling approach, and UI library influence how accessibility must be implemented.
Your specific user base, content type, and interaction patterns determine the most appropriate implementation.
We provide tailored implementation guidance by analyzing your specific technology stack, coding patterns, design system, and project requirements. Our team reviews your codebase and provides custom solutions that integrate seamlessly with your existing architecture.
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