[CSS] explicit text truncation

[pkra]

While both text-overflow: ellipsis; and -webkit-line-clamp (etc) seem explicit enough to consider that authors want to hide the contents from all users, I think user agents do not truncate the text in the accessibility tree. Should this be documented here?

[spectranaut]

Brief discussion in triage to spec/document the current implementations.

[rahimabdi]

Some AT tests:

text-overflow: ellipsis

• iOS VoiceOver 18.3.2 does not truncate
• macOS 15.3.1 & Safari 18.3 does not truncate
• NVDA 2024.1 & Firefox 136.0.2 does not truncate
• JAWS 2024 & Chrome 134.0.6998 does not truncate

webkit-line-clamp (requires display: -webkit-box and -webkit-box-orient: vertical per MDN)

• iOS VoiceOver 18.3.2 does not truncate
• macOS 15.3.1 & Safari 18.3 does not truncate

[pkra]

Same for NVDA and JAWS with Chrome and Firefox. They can even reveal the truncated content in browse mode.

I think everything is very consistent. I just wanted to raise this for documentation since it's a case of text being in the accessibility tree while being visually hidden.

[Since I mentioned it on the call: I filed this issue while looking at tools that work very hard to remove actual content because hidden content can sometimes be noisy for non-visual users.]