Carryover evaluation for CSS anchor positioning

[nairnandu]

Original proposal(s): #752

Tests

• All tests
• Failing tests

We should also consider whether we add tests for CSS anchor positioning focus area in Interop 2026.

[LeaVerou]

Reporting from the preliminary State of HTML 2025 results here! 🙋🏽‍♀️

When we ranked submitted Interop 2026 proposals by number of freeform pain points across the survey mentioning the feature, CSS anchor positioning came in 2nd.
It was also the 3rd web feature¹ by number of interop complaints and the 6th interop pain point topic in general. 80% of the pain points mentioning anchor positioning were about interop.

This becomes even more significant if we consider that CSS was explicitly out of scope for the survey. When CSS features surface regardless, this carries more weight and tends to mean they are especially important to developers.

Sample quotes

We need a solution for popover on hover and ideally an easier to configure and control roving focus that is relative to the anchor position when using the anchor positioning api

HTML APIs such as dialog and popover feel incomplete without also upcoming CSS features like anchor positioning to take full advantage of them

There are various possibilities, but what comes to mind is the practical application of popover attributes and anchor positioning.

position the popover relative to its parent element is not easy, especially when the anchor position is not widely supported

Popover is amazing but because anchor positioning is happening so slowly not really useable in real projects yet

popovers because anchor position is not supported, a popover that isn't anchored properly doesn't work for me

Popover styling relative to the button (tooltip style), keeping it inside viewport with preferred location

Manage the positioning of the elements in pop over, as positioning with anchors is not yet cross browser

Popover anchoring (tried native styling but it did not work for dynamic placement, using floating-ui)

Popups, there seems to be no easy way of opening popup window from element, for example button that would scroll with the browser and open where it has space available. For example colorpicker input type does that partially, but is unable to follow the scroll and is not customizable fully.

please please anchor positioning is not available everywhere yet and it's such a game changer !!!

Css anchor positioning and popovers would work well together but anchor positioning isn't stable

patiently waiting for anchor positioning in safari (i know it's coming soon) and firefox

anchor positioning. i am now using it in prod, with a polyfill, but it's a hassle

There is a related Invoker Relationship, but it is only effective when the target and trigger are one-to-one. However, in practice, there are cases where it is one-to-many. In cases where it is one-to-many, there are cases where the anchor attribute in HTML is useful rather than CSS, so we would like the specification to allow the use of the anchor attribute.

Lack of CSS anchor positioning in all browsers makes adopting popovers untenable

Popovers (because CSS anchoring is not available in all browsers yet)

Dropdowns: I can’t get the anchor-positioning for popovers to work

Footnotes

1. among all features mentioned by respondents, whether they correspond to an Interop 2026 proposal or not ↩