duplicate and/or invalid ID checks

[ricksbrown]

Another audit I would like to port from aria-toolkit, HOWEVER I wanted to check with the team first.

The primary purpose of this audit is to ensure that IDs are unique in the DOM.
I also had a check for invalid IDs (which in HTML5 simply means no whitespace).

The reason I ask about this one is because it is not strictly speaking an accessibility audit - it is more of an HTML validation task.

I felt the duplicate ID check in particular was essential to ARIA (because of IDREFs) and therefore worthy of being part of accessibility tools.

Should I add ID audits?

[alice]

Good question. I wonder if we should limit it to IDs which are actually referred to via any IDREF attribute (mostly ARIA but also label for= and some table attributes IIRC). But that will be incomplete, because naturally many of these attributes change over time (kind of the point of them).

On balance, I think it'll be low noise enough that it's probably worth adding anyway.

[ricksbrown]

I like the idea of limiting it to IDs that are meaningful from an accessibility perspective. You're right though, something like "aria-activedescendant" is likely to change over time and therefore safer to vet them all.

I'll add this audit pretty soon.

[alice]

Great!

[ricksbrown]

Closing this because it's complete.