Last week, we looked at and listened to the symphony of dynamic webpage content. If Session 1 was the quiet theory of Section 508, Session 2 was the loud, blinking, scrolling reality of the web. We tackled the trio of auto-playing audio, moving/blinking content, and auto-updating information, along with a critical detour into flashing content and seizure safety.
Resources
As always, the slides, transcripts, and a condensed summary are available on the respective GDG Vienna event pages as well.
Study Group Session 2
The overarching theme of the session was the Numver 3: Whether it’s a button to pause an audio track, a link to stop a scrolling ticker, or a dialog to hide a live update, the Trusted Tester process demands that the mechanism to control these elements be found within the first three interactive elements a user encounters (or within three elements before or after the moving content).
It’s a strict, pragmatic rule designed to ensure that users aren’t forced to hunt for a “stop” button while being bombarded by sensory input.
Audio Control: The Three-Second Threshold
We started with the basics of audio. If audio plays automatically for more than three seconds, a mechanism must exist to pause, stop, or control the volume independently of the system volume. We walked through several examples: a passing case where a “Stop Ad” button sat right at the top of the page, and a failing case where a “Silent” link was buried fifteen elements deep, forcing keyboard users to tab through a maze just to find relief. The lesson? If the mechanism exists but is hard to find, it fails. Accessibility isn’t just about having a feature; it’s about making it reachable.
Next, we looked at visual motion. Any content that moves, blinks, or scrolls for more than five seconds in parallel with other content requires a pause, stop, or hide mechanism. We debunked a few myths: a loading spinner that prevents interaction is often considered “essential” and thus exempt, but a scrolling news ticker is not. We also saw a clever example where a blinking “Submit” button could be stopped via a keyboard shortcut (Ctrl+S), proving that text instructions can count as a valid mechanism—if they actually work. Unfortunately, we also saw a failing example where the shortcut was documented but broken, reminding us that documentation doesn’t equal functionality.
Auto-Updating Content: Live Regions and Dialogs
The session then shifted to content that changes on its own, like stock tickers or sports scores. Here, the rules are similar: users need a way to pause or hide the updates. But we also introduced the concept of Change Notification. If content updates automatically, how does a screen reader user know? We explored three valid methods: a keyboard-accessible dialog, moving focus to the new content, or using an aria-live region. Using the ANDI tool, we visualized how live regions highlight in purple, making it easier to spot if dynamic content is properly announced. We saw a passing example where a hockey score update was contained in a live region, and a failing one where a dialog box appeared but couldn’t be triggered by keyboard, rendering it useless for many.
Flashing Content: The Seizure Safety Net
Finally, we touched on the most critical safety issue: flashing content. While the Trusted Tester process marks flashing content as “not tested” (since it requires specialized tools like the Photosensitive Epilepsy Analysis Tool - PEAT), we strongly emphasized that this doesn’t mean it’s safe to ignore. Content that flashes more than three times per second can trigger seizures. We reviewed examples where a “stop animation” button existed but was too far down the page, and where blinking text was indistinguishable from flashing. The takeaway: even if the formal test says “not tested,” the ethical and safety obligation to prevent seizures remains.
Knockout Criteria
A recurring point in the session was the “knockout” nature of these tests. If a mechanism fails any applicable test condition (like color contrast on a “Pause” button, or keyboard accessibility on a dialog), the entire feature fails. It’s a rigorous standard that leaves no room for partial credit.
Homework
Your task this week is to complete the knowledge checks for auto-playing, auto-updating, and flashing content. If you haven’t installed ANDI or the TPGI Color Contrast Checker yet, now is the time! You will need them.
Next Session
Get ready for a deep dive into Keyboard Access and Focus. This is a massive topic, so we’ve moved the next session to Thursday, March 12th at 18:00 GMT+1 (note the day and time change!). We’ll be covering focus order, visible indicators, and keyboard traps. It’s going to be a long one, so bring your coffee.