Two primary goals: - Be able to embed iframes that have same-origin as other frames in the frame tree but not be able to directly script them. - Have a same-origin iframe with other iframes be in a separate event loop.


Allowing cross-document DOM access has made the web very complicated. Wouldn't it be nice if individual pages could opt themselves or their frames into a simplier mode which didn't allow cross-document access?



Editor's draft

Status in Chromium


In development (tracking bug) in:

  • Chrome for desktop release In development
  • Chrome for Android release 87
  • Android WebView release 87

Consensus & Standardization

After a feature ships in Chrome, the values listed here are not guaranteed to be up to date.


Last updated on 2021-03-10