The WCAG Explained

Summary:
WCAG 2.3, "Seizures and Physical Reactions," aims to protect users from content that could induce seizures or physical reactions, particularly focusing on visual elements that flash or blink. This is vital for ensuring the safety of users with photosensitive epilepsy or other seizure disorders.

What:
This guideline requires that web content does not contain anything that flashes more than three times in any one-second period, to prevent the risk of seizures.

1. 2.3.1 Three Flashes or Below Threshold: Web pages do not contain anything that flashes more than three times in any one-second period.
2. 2.3.2 Three Flashes: Web pages do not contain anything that flashes more than three times in any one-second period if the flashes are bright and large enough to cover a significant portion of the screen.
3. 2.3.3 Animation from Interactions: Motion animation triggered by interaction can be disabled unless the animation is essential to the functionality or the information being conveyed.

Why:
Flashing content can be a serious hazard for some users, potentially triggering seizures or physical reactions. By adhering to these guidelines, web developers can prevent such risks, making the web a safer environment for all users, especially those susceptible to seizures.

Examples and Scenarios:

1. Avoiding Flashing Ads: Advertisements or promotional banners should not contain fast or bright flashing elements.
2. Safe Animations: Ensure that any animations on the site, especially those that start automatically, do not flash or blink rapidly.
3. Interactive Elements: For interactive elements that trigger animations, provide an option to disable animations for users who are sensitive to motion.

How to Comply:

• Websites: Carefully design and test web content to ensure it adheres to the flashing thresholds. Use tools to analyze and monitor the flashing rate of any animations or interactive elements.
• Mobile Apps: Design app interfaces and interactions without elements that flash rapidly. Provide user controls to disable animations where possible.
• Software Applications: Implement features and design elements in a way that avoids rapid flashing or blinking. Offer settings to control or disable animations that could cause discomfort or seizures.

Exceptions:

• Essential Flashing Content: If the flashing is essential for the message or function (which is rare), this should be carefully assessed and minimized. However, you are generally encouraged to find alternatives to flashing content.