Bugzilla

This bug was originally filed about visual support of the abbr attribute.

That said, Firefox already exposes `<th abbr=...>` as per [the spec](https://w3c.github.io/html-aam/#html-attribute-state-and-property-mappings), at least for Windows and Linux:
`Object attributes: "abbr"`
In your example, Firefox exposes an abbr attribute with a value of "Tuesday". It's up to ATs as to whether/how they consume this. NVDA does not; see https://github.com/nvaccess/nvda/issues/3566.

It was specified this way so that ATs could still access the visually rendered content as well, which is important because we shouldn't assume that AT users always want the alternative version.

Your example is interesting because the abbr attribute is specified as providing a shorter version of the content, yet here, you use it to specify a longer version.

Note that exposing it as the accessible name wouldn't necessarily mean that screen readers will read it as a replacement for the content anyway. For example, if you use aria-label instead of abbr in your example, NVDA does not read "Tuesday" as the column header. The name does not (and should not) always trump the content. It depends on the role.

This bug was originally filed about visual support of the abbr attribute.

That said, Firefox already exposes `<th abbr=...>` as per [the spec](https://w3c.github.io/html-aam/#html-attribute-state-and-property-mappings), at least for Windows and Linux:

> Object attributes: "abbr"

In your example, Firefox exposes an abbr attribute with a value of "Tuesday". It's up to ATs as to whether/how they consume this. NVDA does not; see https://github.com/nvaccess/nvda/issues/3566.

It was specified this way so that ATs could still access the visually rendered content as well, which is important because we shouldn't assume that AT users always want the alternative version.

Your example is interesting because the abbr attribute is specified as providing a shorter version of the content, yet here, you use it to specify a longer version.

Note that exposing it as the accessible name wouldn't necessarily mean that screen readers will read it as a replacement for the content anyway. For example, if you use aria-label instead of abbr in your example, NVDA does not read "Tuesday" as the column header. The name does not (and should not) always trump the content. It depends on the role.