unprefix the `-webkit-user-select` CSS property

[o-t-w]

Description

The user-select CSS property still needs a -webkit- prefix in Safari.

A note about the current state of CSS vendor prefix’s

• Chrome, Edge and other Chromium-based browsers had required a -webkit- prefix for print-color-adjust. This is no longer the case as of version 136.
• As part of Interop 2025, Safari removed the need for the -webkit- prefix for the text-decoration CSS shorthand property.

That leaves only a handful of properties requiring a prefix:

• user-select
• stretch: Implemented as -webkit-fill-available in WebKit and -moz-available in Firefox.
• text-size-adjust: Needs -webkit- prefix in WebKit and Firefox. (Firefox also supports the -moz- prefix.)
• box-decoration-break: Needs -webkit- prefix in WebKit.
• line-clamp: Needs a -webkit- prefix and some additional non-standard properties (display: -webkit-box and -webkit-box-orient: vertical) to be set in Chromium, WebKit and Firefox.

Autoprefixer is downloaded from NPM 33 million times per week. Needing to complicate build tooling with Autoprefixer for such a tiny handful of properties is an unfortunate situation.

Of those properties that do require a prefix, some are pretty niche, but that can’t be said for user-select. While line-clamp is another very useful and popular CSS feature that requires a prefix, Autoprefixer doesn’t prefix line-clamp, so it is primarily user-select that necessitates continued use of Autoprefixer). While ideally no property would require a prefix, for the reason just stated user-select in particular should be prioritised.

Specification

https://drafts.csswg.org/css-ui-4/#content-selection

web-feature

https://web-platform-dx.github.io/web-features-explorer/features/user-select/

Test Links

https://wpt.fyi/results/css/css-ui?label=master&label=experimental&aligned&q=user-select

Additional Signals

WebKit issue
Unmerged PR
various open bugs.

[github-actions]

This comment was automatically generated based on the information you provided. Please don't edit it.

Below is additional information about the web feature (from the web-features project) which is referenced in your proposal.
If this doesn't accurately correspond to your proposal, please update your initial comment to include web-features: <feature-id>.
To find feature IDs, use the web-features explorer.

Feature user-select

• ID: user-select
• Name: user-select
• Description: The user-select CSS property controls which elements can be selected by the user.
• Baseline status: Limited Availability
• Docs: user-select
• WPT tests: wpt.fyi/results/?q=feature:user-select
• More information: See the web-features explorer

[foolip]

@o-t-w thank for submitting this proposal! I took the liberty of editing your description to link https://web-platform-dx.github.io/web-features-explorer/features/user-select/, in order to help the bot (above) pick out the right feature for this.

[dholbert]

Test Links

https://wpt.fyi/results/css/css-ui?label=master&label=experimental&aligned&q=user-select

One suggested refinement to the Test Links here:

Right now the tests exercise the contain value for user-select, but no browser supports that keyword (and it's not mentioned above), so I suspect we're not intending for this interop focus-area to be a forcing factor on all browsers implementing it.

Specifically these tests have subtests that check for user-select:contain (which fail in Chromium/Gecko/WebKit):
https://wpt.fyi/results/css/css-ui/parsing/user-select-computed.html
https://wpt.fyi/results/css/css-ui/parsing/user-select-valid.html
https://wpt.fyi/results/css/css-ui/user-select-inheritance.html

So: if this proposal is adopted, I suggest that we either:
(A) fork these^ tests so that user-select: contain is tested in a separate tests (which will not be part of the interop set of tests). Maybe user-select-computed-contain.html which is a copy of user-select-computed.html just to test that one value, for example. (Slightly clumsy, but we do it sometimes for the benefit of the interop project.)

...or:
(B) Just remove those 3 tests entirely; they're basic smoke-tests for properly handling the property in CSS, but the remaining tests likely cover that pretty well, too.)

Maybe for now it's best to just plan for (B) since it's simplest, and we can do (A) if & when the proposal is adopted, if we want to add a bit more test coverage.

[frivoal]

-webkit-user-select is required (for compat) by the spec:

For compatibility with legacy content, UAs that support user-select must also support -webkit-user-select as an alias.

If we have evidence that it is not actually needed for compat, we should drop it from the spec AND the tests. Otherwise, it would probably be a good idea to test usage of prefixed and unprefixed separately, so splitting/rewriting the tests would makes sense, but I don't think it's appropriate to just remove the prefixed version from all tests generally.

[wpt-interop]

Thank you for proposing unprefix the -webkit-user-select CSS property for Interop 2026.

We are pleased to let you know that it has been accepted as part of the Web compat focus area.

You’ll be able to track progress on this topic throughout the year via the Interop 2026 dashboard.

Posted on behalf of the Interop team.