Filed under “Missed First Time Around.” It appeared in the Firefox 139 release notes and caught my attention. Then I discovered that it’s been in Chrome since at least 2022. As I wrote this, it appeared in Safari Technology Preview 125. So there you have it.
There are several good posts and tutorials about hidden=until-found available, so I thought I’d jot down a few key takeaways for future reference.
It makes hidden content “findable”
Short story: Adding hidden=until-found to an HTML element allows any hidden content within to be findable in the browser using in-page search.
You’ll notice, or more accurately not notice, that the content is hidden with that in place:
