LGTM2

On Friday, September 19, 2025 at 3:16:37 AM UTC+2 Domenic Denicola wrote:

LGTM1.

While it's unfortunate that the path to interop here might take longer than 
we've hoped, it's very clear from the abundant linked documentation that 
the team has done everything possible to set this feature up for success, 
and meet the high bar set by our process. The spec PR has received detailed 
review; the WPTs are comprehensive; a polyfill is ready; and perhaps most 
importantly, the API has gathered ~3.5 years worth of broad feedback which 
has shaped and improved it substantially. In my opinion, there's nothing 
more we could ask for, from an API owners perspective.
On Friday, September 19, 2025 at 5:38:28 AM UTC+9 Mason Freed wrote:

Contact emails

[email protected], [email protected]

Explainer

https://open-ui.org/components/interest-invokers.explainer

Specification

https://github.com/whatwg/html/pull/11006

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

https://drafts.csswg.org/selectors/#interest-pseudos

Summary

This feature adds an `interestfor` attribute to <button> and <a> elements. 
This attribute adds "interest" behaviors to the element, such that when the 
user "shows interest" in the element, actions are triggered on the target 
element, such as showing a popover. The user agent will handle detecting 
when the user "shows interest" in the element, via methods such as hovering 
the element with a mouse, hitting special hotkeys on the keyboard, or 
long-pressing the element on touchscreens. When interest is shown or lost, 
an `InterestEvent` will be fired on the target, which have default actions 
in the case of popovers - showing and hiding the popover.

Blink component

Blink>DOM 
<https://issues.chromium.org/issues?q=customfield1222907:%22Blink%3EDOM%22>

Web Feature ID

https://github.com/web-platform-dx/web-features/pull/3275

Search tags

interestfor <https://chromestatus.com/features#tags:interestfor>, invokers 
<https://chromestatus.com/features#tags:invokers>

TAG review

https://github.com/w3ctag/design-reviews/issues/1058

TAG review status

Issues addressed

Origin Trial Name

The interesttarget Attribute

Chromium Trial Name

HTMLInterestTargetAttribute

Origin Trial documentation link

https://open-ui.org/components/interest-invokers.explainer

WebFeature UseCounter name

kInterestTarget

Risks


Interoperability and Compatibility

Note: There are interop issues due to WebKit. WebKit has expressed 
opposition 
<https://github.com/whatwg/html/issues/10309#issuecomment-3266951344> to 
supporting the "tooltip" use case, citing the lack of "a consistent and 
reliable way to get to tooltip-like information [on touchscreen]". This is 
despite *long-press* being the de-facto standard for exactly that 
interaction pattern, for at least a decade if not longer. See, for example, 
UIKit's 
long-press documentation 
<https://developer.apple.com/documentation/uikit/handling-long-press-gestures>, 
the following comment 
<https://github.com/whatwg/html/issues/10309#issuecomment-3267037840> on 
the standards issue, and a similar comment 
<https://github.com/WebKit/standards-positions/issues/305#issuecomment-2493546945>
 
from a year ago which also did not receive a response by WebKit. In 
addition, WebKit's opinion states that they are unable to identify an 
interface mechanism for `interestfor` on spatial computing devices. I've 
suggested 
<https://github.com/WebKit/standards-positions/issues/305#issuecomment-2287429935>
 
that one option is to mandate a particular behavior for these devices, but 
that comment was ignored.


Am I wrong to think that if a future mobile interaction would be a better 
fit for showing "interest" than long-press, UAs can simply wire it to use 
this APIs semantics?
 


Importantly, the TAG review was marked Supportive 
<https://github.com/w3ctag/design-reviews/issues/1058> for this overall API 
proposal.

Gecko: Defer <https://github.com/mozilla/standards-positions/issues/1181> 
The comments are generally supportive, but without going so far as to mark 
the issue with "Support". The general tone is supportive of "option 3", 
which is the one being pursued, to add an item to the context menu on 
mobile interfaces.


Again, the implemented option feels like a UX decision by the browser and 
can change over time, right?
(I personally prefer option 2 or even option 4 + extra tap to open the 
menu, but what do I know..)
 


WebKit: Negative <https://github.com/WebKit/standards-positions/issues/464> 
This position is not explicitly marked as negative, but the comments 
(including in the linked HTML issue) are negative: "We therefore remain 
opposed to this feature"

Web developers: Strongly positive 
<https://github.com/mozilla/standards-positions/issues/1181#issuecomment-3097924236>
 
See the linked comment, for a summary of developer opinions from multiple 
venues. Developers are highly positive on this feature, recognizing the 
fact that 94+% 
<https://docs.google.com/spreadsheets/d/11Bt_FCAqu1hd5llGRGpzgwlgHaqLmOC4SJEMRtNQY-g/edit?gid=0>
 
of top-50 production sites use some form of hover-triggered UI.


With my Shopify hat on, I can attest to the developer need for this.
 


Other signals:

Ergonomics

The `popover=hint` API is a fairly important companion API to this one, 
providing a way to *not* close other unrelated `popover=auto` popover 
stacks when a tooltip UX is shown.

Activation

There is a polyfill <https://github.com/mfreed7/interestfor> which can be 
used to mitigate a lack of browser support. See the explainer's touchscreen 
section 
<https://open-ui.org/components/interest-invokers.explainer/#touchscreen> for 
more detail, but since users need to maintain access to the UA-provided <a> 
long-press context menu, it isn’t possible for the polyfill to support 
touchscreen long-press on <a> elements without canceling the context menu. 
Importantly, however, due to this same limitation, almost no production 
sites today support touchscreen activation of hovercards on links. So the 
activation story should be fairly good: no loss of functionality on 
browsers relying on the polyfill, and an enhanced story on touchscreen for 
browsers natively supporting the feature.

WebView application risks

Does this intent deprecate or change behavior of existing APIs, such that 
it has potentially high risk for Android WebView-based applications?

There should not be any WebView risk. It's possible that if WebView apps 
suppress the context menu, then content that uses `interestfor` will not be 
available within those apps. However, presumably in such an app, the long 
press gesture is already being intercepted to provide a tooltip or 
app-provided menu, and that will continue to function.


Debuggability

None

Will this feature be supported on all six Blink platforms (Windows, Mac, 
Linux, ChromeOS, Android, and Android WebView)?

Yes

Is this feature fully tested by web-platform-tests 
<https://chromium.googlesource.com/chromium/src/+/main/docs/testing/web_platform_tests.md>
?

Yes: https://wpt.fyi/results/html/semantics/interestfor

Flag name on about://flags

Experimental Web Platform Features

Finch feature name

HTMLInterestForAttribute

Rollout plan

Will ship enabled for all users

Requires code in //chrome?

False

Tracking bug

https://issues.chromium.org/issues/326681249

Availability expectation

Unknown, due to WebKit objections.

Adoption expectation

With the polyfill <https://github.com/mfreed7/interestfor>, it is my hope 
that adoption can proceed for some sites before Baseline status. That 
remains to be seen.

Estimated milestones
Shipping on desktop142Origin trial desktop first135Origin trial desktop last
137Origin trial extension 1 end milestone140DevTrial on desktop133Shipping 
on Android142Origin trial Android first135Origin trial Android last137DevTrial 
on Android133Shipping on WebView142Origin trial WebView first135Origin 
trial WebView last137

Anticipated spec changes

Open questions about a feature may be a source of future web compat or 
interop issues. Please list open issues (e.g. links to known github issues 
in the project for the feature specification) whose resolution may 
introduce web compat/interop risk (e.g., changing to naming or structure of 
the API in a non-backward-compatible way).

Since WebKit is objecting to the feature, the HTML spec PR 
<https://github.com/whatwg/html/pull/11006> cannot land. It's possible that 
in the future, when WebKit reviewers give it a review, they find things 
that they would like to change. Given all of the opportunities provided to 
them to give this feedback early, we should be highly reluctant to make 
such changes. However, they are at least possible. The CSS specs have 
landed in drafts (https://drafts.csswg.org/css-ui-4/#interest and 
https://drafts.csswg.org/selectors/#interest-pseudos). Those were the 
result of active discussions in the CSSWG on multiple occasions, with 
significant feedback from the participants. So I would consider those to be 
lower risk of changing.

Link to entry on the Chrome Platform Status

https://chromestatus.com/feature/4530756656562176?gate=6100172066258944

Links to previous Intent discussions

Intent to Prototype: https://groups.google.com/a/ch
romium.org/d/msgid/blink-dev/B7F891EB-32FE-48FD-B54B-E452AD
74CC3E%40igalia.com

Intent to Experiment: https://groups.google.com/a/ch
romium.org/d/msgid/blink-dev/CAM%3DNeDiTCMXnR6D-5XdYiwgV_
FMAKE8VM%2Bq-Pyho9KZqoDpSjQ%40mail.gmail.com

Intent to Extend Experiment 1: https://groups.google.com/a/ch
romium.org/d/msgid/blink-dev/CAM%3DNeDhZosgitNVTVqQ%3DzznM0
JxiH8d0ZoGBManBaE6ByUJ0%2Bg%40mail.gmail.com


This intent message was generated by Chrome Platform Status 
<https://chromestatus.com/>.




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