w3c
Add accessibility section
If the browser is in the control of presenting the badge, it should be possible to define some accessibility guidelines.
e.g. around spammy changing the badge too many times in quick succession, which is disproportionately annoying for voice users.
Put both a) a note for developers to not do this. b) a recommendation to user agents to debounce and/or throttle changes to badge state when reading them out.
If it helps, badges are handled reasonably well for screen reader users in software.
In iOS for example, I'll hear something like "Twitter, 25 new items". I tend to turn off such things on my (Windows 10) laptop, but the one I do have running is Slack, and it sadly just tells me "1 unread message" without the context of the app name itself (which is unhelpful).
The information doesn't get announced in real-time as the number of messages changes. I get notifications for incoming tweets, messages etc. but I don't hear the badge updating - that's just on inspection.
Based on @LJWatson's comment, it might be worth while to see if we can provide a free form text input that can serve as the visual equivalent of what is being badged ... like:
- "4 unread emails".
- "2 upcoming events".
Where the application name could be derived from the installed application or the document's title.
And default case, the OS would announce "X new items". This is what MacOS does with VoiceOver - but we have the possibility to provide a better experience when badging tabs.