From experience, it can be a bit slow to get hold of sites willing to
experiment so 3 milestones might be a bit short. Either way, you have
the required lgtm so good luck! It seems like a useful API. And you can
request an extension if it's not enough.
/Daniel
On 2026-03-24 20:12, 'Stephanie Zhang' via blink-dev wrote:
Thanks for the review, Alex!
No existing Range-producing APIs are modified. OpaqueRange is a new
type created only via the new createValueRange() method. It extends
AbstractRange rather than Range, so existing APIs are unaffected.
We’d like to validate the API shape with developers first,
particularly the value-offset model for real use cases like inline
suggestions and highlights. We don’t have specific partners lined up
today, but we plan to reach out to potential partners during the
experiment and hope to learn from interested developers as well.
*From:*Alex Russell <[email protected]>
*Sent:* Monday, March 23, 2026 11:44 AM
*To:* blink-dev <[email protected]>
*Cc:* Stephanie Zhang <[email protected]>
*Subject:* [EXTERNAL] Re: Intent to Experiment: OpaqueRange
You don't often get email from [email protected]. Learn why
this is important <https://aka.ms/LearnAboutSenderIdentification>
First, thanks for the thorough and code-focused Explainer; nicely done.
Are any of the existing Range-producing APIs modified here? I.e., do
they now return OpaqueRange objects rather than (transparent) Range
responses if, e.g., they happen to include an <input>?
Also, are there any reasons not to ship now? E.g., are there partners
lined up waiting to try OpaqueRange that we can learn from?
Regardless, LGTM1 to experiment for 3 releases.
On Monday, March 23, 2026 at 11:29:56 AM UTC-7 Stephanie Zhang wrote:
*Contact emails*
[email protected] <mailto:[email protected]>,
[email protected] <mailto:[email protected]>,
[email protected] <mailto:[email protected]>,
[email protected] <mailto:[email protected]>
*Explainer*
https://github.com/MicrosoftEdge/MSEdgeExplainers/blob/main/OpaqueRange/explainer.md
<https://github.com/MicrosoftEdge/MSEdgeExplainers/blob/main/OpaqueRange/explainer.md>
*Specification*
https://github.com/whatwg/dom/pull/1404
<https://github.com/whatwg/dom/pull/1404>
*Summary*
OpaqueRange represents a live span of text within a form control’s
value (for example, a <textarea> or text <input>), so developers
can work with value text using range-like APIs. It enables
operations like getBoundingClientRect(), getClientRects(), and use
with the CSS Highlights API for UI such as inline suggestions,
highlights, and anchored popovers. It preserves encapsulation by
exposing only value offsets (and returning null for
startContainer/endContainer), so DOM endpoints and internal
structure aren’t exposed.
*Blink component*
Blink>DOM
<https://issues.chromium.org/issues?q=customfield1222907:%22Blink%3EDOM%22>
*Web Feature ID*
Missing feature
New feature ID for OpaqueRange · Issue #3863 ·
web-platform-dx/web-features
<https://github.com/web-platform-dx/web-features/issues/3863>
*TAG review*
https://github.com/w3ctag/design-reviews/issues/1206
<https://github.com/w3ctag/design-reviews/issues/1206>
*TAG review status*
Pending
*Goals for experimentation*
Validate API design and gather developer feedback on whether the
API meets their needs.
*Risks*
*Interoperability and Compatibility*
OpaqueRange adds new methods (e.g., createValueRange()) to
<textarea> and text <input> elements so authors can create ranges
over value text. It doesn’t change existing editing or selection
behavior, so the risk to existing sites is low. The main
interoperability risk is lack of implementation across engines,
which could make text-anchored UI or highlights inside native
controls work in only some browsers.
/Gecko/: No
signal (https://github.com/mozilla/standards-positions/issues/1289
<https://github.com/mozilla/standards-positions/issues/1289>)
/WebKit/: No
signal (https://github.com/WebKit/standards-positions/issues/541
<https://github.com/WebKit/standards-positions/issues/541>)
/Web developers/:
Positive (https://github.com/w3c/csswg-drafts/issues/10346
<https://github.com/w3c/csswg-drafts/issues/10346>) Another
positive example: https://github.com/whatwg/html/issues/11478
<https://github.com/whatwg/html/issues/11478>
/Other signals/:
*Ergonomics*
OpaqueRange is typically used with selection offsets and with
geometry/highlighting APIs. The geometry calls are synchronous and
can trigger layout, similar to existing Range geometry methods.
Since the range is live, offsets are updated as the control’s
value is edited.
*Activation*
Moderate. Developers need to learn the value-offset model and how
it differs from Range (there are no DOM endpoints).
*Security*
No new data exposure beyond existing access to form control values
and selection. Exposes only value offsets and geometry and does
not expose internal DOM (startContainer/endContainer are null).
*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?/
Low. OpaqueRange adds a new method to <textarea> and text <input>
elements, but does not change or deprecate any existing behavior
*Ongoing technical constraints*
None
*Debuggability*
No DevTools changes required.
*Will this feature be supported on all six Blink platforms
(Windows, Mac, Linux, ChromeOS, Android, and Android WebView)?*
Yes
Works on all platforms that support <input> and <textarea> elements.
*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/dom/ranges/tentative?label=experimental&label=master&aligned
<https://wpt.fyi/results/dom/ranges/tentative?label=experimental&label=master&aligned>
*Flag name on about://flags*
N/A
*Finch feature name*
OpaqueRange
*Requires code in //chrome?*
False
*Tracking bug*
https://issues.chromium.org/issues/421421332
<https://issues.chromium.org/issues/421421332>
*Measurement*
UseCounter `OpaqueRange` measures successful creation of
OpaqueRange objects on <textarea> and text <input> elements.
*Estimated milestones*
Origin trial desktop first
148
DevTrial on desktop
148
Origin trial Android first
148
DevTrial on Android
148
*Link to entry on the Chrome Platform Status*
https://chromestatus.com/feature/6297362687066112?gate=5151419728134144
<https://chromestatus.com/feature/6297362687066112?gate=5151419728134144>
*Links to previous Intent discussions*
Intent to Prototype:
https://groups.google.com/a/chromium.org/d/msgid/blink-dev/LV9PR21MB5189A114B34C8A3685A3C4A4805CA%40LV9PR21MB5189.namprd21.prod.outlook.com
<https://groups.google.com/a/chromium.org/d/msgid/blink-dev/LV9PR21MB5189A114B34C8A3685A3C4A4805CA%40LV9PR21MB5189.namprd21.prod.outlook.com>
This intent message was generated by Chrome Platform Status
<https://chromestatus.com/>.
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