For users on slow connections such as 2G, the performance penalty from third-party scripts loaded via document.write is often so severe as to delay display of main page content for tens of seconds. This feature will block the load of cross-origin, parser-blocking scripts inserted via document.write in case of an HTTP cache miss for users on a 2G connection. The feature will only be applicable to such scripts in the main frame.



Specification link

Unknown standards status - check spec link for status

Status in Chromium


Browser Intervention (tracking bug)

Consensus & Standardization

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

  • No signal
  • No signal
  • Positive


Search tags


Last updated on 2021-10-09