Allows developers to selectively enable and disable the use of media elements (<img> and <video>) without specified dimensions through the Feature-Policy HTTP header or the <iframe> 'allow' attribute. This provides more control over media elements with unspecified dimension, on a per-origin basis. Use this policy to improve layout stability. The identifier for the feature in policies is 'unsized-media'. By default, 'unsized-media' is allowed in all frames.



Status in Chromium


No active development (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
  • No signals


Last updated on 2021-05-13