CSS URL Request Modifiers

[dumbmoron]

Specification

https://drafts.csswg.org/css-values-5/#request-url-modifiers

Description

CSS URL request modifiers allow authors to control fetch behavior for resources loaded via the url() function by specifying cross-origin(), integrity(), and referrer-policy() modifiers after the URL string. For example: background-image: url("image.png" cross-origin(anonymous) referrer-policy(no-referrer)).

Documentation

https://drafts.csswg.org/css-values-5/#request-url-modifiers

Browser support

Safari/WebKit: Shipped (cross-origin and referrer-policy; integrity gated behind separate flag)
Chromium: Implementation in progress (by me) - https://chromestatus.com/feature/5111997147512832
Firefox: Not implemented

[ddbeck]

Hi @dumbmoron, thanks for filing this issue. edited the issue description to link to a likely Chrome Platform Status entry; please say something if there's a better link for this feature.

Other stuff, mostly for me:

• We might want to split this up into distinct features, for each of the modifiers, at least at first.

• There is no data about this in BCD. Needs upstream work to mint a feature. It is mentioned in the Safari 26.2 release notes.

• I can't find anything about this from Mozilla. No standards position or implementation bug at this time.

• Rough description in web-features's style:

  The url() CSS function accepts modifiers, such as cross-origin() and referrer-policy(), to limit loading subresources.

• WPT: https://wpt.fyi/results/css/css-values/urls?label=master&label=experimental&aligned&q=css%2Fcss-values%2Furls%2Furl-request-modifiers

[dumbmoron]

Hi @dumbmoron, thanks for filing this issue. edited the issue description to link to a likely Chrome Platform Status entry; please say something if there's a better link for this feature.

Looks good to me, thanks!

• I can't find anything about this from Mozilla. No standards position or implementation bug at this time.

I opened a mozilla standards position issue: mozilla/standards-positions#1386

[ddbeck]

I've sent mdn/browser-compat-data#29440 upstream to create BCD keys.