Caution
This document is an English translation of the “freee Accessibility Guidelines.” The normative version of this document is in Japanese, and the English version is informational. The English translation is incomplete, and any links with their link texts left in Japanese are untranslated. Please be aware that there may be inaccuracies in the translation or parts that are outdated.
Issues with Content Changing Automatically
Some users with cognitive or attention disabilities may find it difficult to understand information when the following types of content are displayed on the same page along with other content:
Automatically updated
Moving
Flashing
Auto-scrolling
If these dynamic changes do not occur automatically or only last for a short period, such content is generally not problematic. However, in cases where they persist, WCAG requires that users be able to control these dynamic changes.
Furthermore, stricter WCAG success criterion prohibits interruptions, such as push notifications, except in emergencies. Interruptions can not only break the concentration of users with cognitive or attention disabilities, but can also disrupt screen reader users, causing confusion by interrupting the reading of information. To avoid such confusion, WCAG allows interruptions only when it is needed for protecting health, property, or safety.
If brightness alternates at a specific frequency (causing a flashing effect) within a certain area of the page, it may trigger photosensitive seizures in some users. WCAG’s Level A success criterion allows flashing under certain conditions. On the other hand, the Level AAA success criterion sets a stricter condition, allowing no more than 3 flashes per second in any situation. However, it may be difficult to precisely meet or verify compliance with the limited conditions of Level A. Since this is a matter of user safety, freee has adopted the stricter Level AAA success criterion.
Reference: This success criterion was added in response to the so-called Pokémon Shock incident.