Intent to Deprecate and Remove: "on-demand" value for hover/any-hover media queries.

ยอดดู 102 ครั้ง

Mustaq Ahmed

7 มี.ค. 2560 10:43:357/3/60
ถึง blink-dev

Primary eng (and PM) emails


Remove the support for “hover: on-demand” and “any-hover: on-demand” media queries. The “on-demand” value is satisfied for the pointing devices that, for example, “can't normally hover, but will activate hover on a long press”.

After the proposed change, a pointing device that used to satisfy the “on-demand” value would satisfy the “none” value instead.


The “on-demand” value for hover/any-hover media queries has been removed from the spec about a year ago because it doesn’t seem to have a convincing use case.

Spec change:

Spec discussion:

Compatibility And Interoperability Risk

The risk of breakage is low because of low usage. We manually tested selected existing sites (among the few we found) that contain “hover: on-demand”, and found them working fine with the proposed change. See Usage Information below for details.

The interop risk is also low since mobile Safari doesn’t support “on-demand”, and Firefox doesn’t even support hover/any-hover media queries ( Edge has a bug to remove “on-demand” support (

Alternative implementation suggestion for web developers

After the change, web developers should use “hover: none” and “any-hover: none” instead of “hover: on-demand” and “any-hover: on-demand” respectively.

Usage information

UseCounter data: So far we have data available from M57 beta (and dev as well) which shows that ~0.02% page visits parse the “on-demand” CSS value.

HttpArchive data: In the 2015-01-15 dataset, there are ~35 sites matching r"hover:\s*on-demand" (out of 16.7M entries). We manually checked the top ones among those ~35 sites (more precisely, the ones with ranking <50k) using a Chromium build that doesn’t support “on-demand”, and found all of them working fine:

OWP launch tracking bug

Entry on the feature dashboard

Requesting approval to remove too?


Chris Harrelson

10 มี.ค. 2560 12:58:2110/3/60
ถึง Mustaq Ahmed, blink-dev

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Dimitri Glazkov

11 มี.ค. 2560 11:00:5311/3/60
ถึง Chris Harrelson, Mustaq Ahmed, blink-dev

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Jochen Eisinger

16 มี.ค. 2560 13:32:2416/3/60
ถึง Dimitri Glazkov, Chris Harrelson, Mustaq Ahmed, blink-dev
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