Bug 227967 – Implement CSS module scripts

• Component: CSS
• Status: RESOLVED FIXED

[[e-mail]]

The CSS module scripts feature has been merged into the HTML spec.

Spec: https://html.spec.whatwg.org/multipage/webappapis.html#creating-a-css-module-script
Spec Integration PR: https://github.com/whatwg/html/pull/4898

[Radar WebKit Bug Importer]

<rdar://problem/80917329>

[Westbrook]

Now that the import attributes spec has re-advanced to stage 3 (https://tc39.es/proposal-import-attributes/), any thoughts on when we might see this work resourced?

[jogibear9988]

Chromestatus:
https://chromestatus.com/feature/5205869105250304

Firefox issue about import attributes:
https://bugzilla.mozilla.org/show_bug.cgi?id=1736059

Firefox issue about Module CSS Scripts:
https://bugzilla.mozilla.org/show_bug.cgi?id=1720570

Any updates on when this might be out? Sure would be nice to be able to use this in production apps as it makes things load really nicely in Chrome and Edge but I have to opt for less attractive and old techniques because of Safari.

Is there any kind of eta of releasing import with type CSS? Being able to import CSS would be a game changer. I know because I wrote my app with it but only tested with chrome like a noob. I had to revert everything to accommodate FF and Safari.

How's this going? Having the ability to confidently import CSS across browsers will be huge for browser development.

[jogibear9988]

FF will ship it in one of the next Versions: https://bugzilla.mozilla.org/show_bug.cgi?id=1720570#c10

[Casey Klebba]

It would be great to have some sort of signal on intent/desire to ship this capability, even if timing/priority is not known at this time — thanks for considering

[Herman C. Enos]

Any updates on this feature? It’s pretty crucial for the future of framework-free web apps.

[Casey Klebba]

Checking in on this thread for any new signs. Best I have found is an older thread which indicates support on 2023-11-14: https://github.com/WebKit/standards-positions/issues/77

Import attributes with {type: 'css'} availability:

Chrome 123 (Release date: ⁨2024-03-19⁩)
Firefox 147 (Release date: ⁨2026-01-13⁩)

https://webstatus.dev/features/css-modules

This currently works in Chrome, Firefox, Edge, and Opera, but fails in Safari due to what appears to be a WebKit-specific issue with CSS imports.

At the moment it’s difficult to justify adding browser-specific workarounds for Safari when the behavior diverges from every other major browser engine. Any clarification on whether this behavior is intentional or planned to be addressed would be appreciated.

[Casey Klebba]

For reference, here are all Interop request/rejection threads for CSS Module Scripts:

2026: CSS Module Scripts #1056 — https://github.com/web-platform-tests/interop/issues/1056
2025: CSS Module Scripts #703 — https://github.com/web-platform-tests/interop/issues/703
2024: CSS Module Scripts #597 — https://github.com/web-platform-tests/interop/issues/597
2023: CSS Module Scripts #206 — https://github.com/web-platform-tests/interop/issues/206

It would be great to see this issue have an assignee or any disposition indicating an intent to implement

Thank you for considering

[Kiet Ho]

Pull request: https://github.com/WebKit/WebKit/pull/72110

Amazing to see a PR up for this — thanks so much for prioritizing ❤️

[Kiet Ho]

Pull request: https://github.com/WebKit/WebKit/pull/74961

[Kiet Ho]

*** Bug 222750 has been marked as a duplicate of this bug. ***

[Kiet Ho]

Submitted web-platform-tests pull request: https://github.com/web-platform-tests/wpt/pull/63294

[EWS]

Committed 322887@main (b1913f6615d4): <https://commits.webkit.org/322887@main>

Reviewed commits have been landed. Closing PR #74961 and removing active labels.