> syntax as follows:
- <supports-feature> = <> | <>
- | <> | <>
+ <supports-feature> = <>
+ | <> | <>
+ | <>
+ | <>
<supports-font-tech-fn> = font-tech( <> )
<supports-font-format-fn> = font-format( <> )
+ <supports-at-rule-fn> = at-rule( <> )
-
- at-supports-font-format-001.html
- at-supports-font-tech-001.html
- js/CSS-supports-L5.html
-
-
: <>
::
The result is true if the UA
@@ -138,9 +135,24 @@ Extensions to the ''@supports'' rule
supports the font format
provided as an argument to the function.
+ : <>
+ ::
+ The result is true if the UA
+ supports the at-rule
+ provided as an argument to the function.
+
Extensions to the definition of support
+
+Font techs and formats
+
+
+ at-supports-font-format-001.html
+ at-supports-font-tech-001.html
+ js/CSS-supports-L5.html
+
+
A CSS processor is considered to
support a font tech
when it is capable of utilizing the specified [[css-fonts-4#font-tech-definitions]]
@@ -152,6 +164,21 @@ Extensions to the definition of support
in layout and rendering,
and this format is not specified as a <>.
+
+At-rules
+
+
+ js/supports-at-rule.html
+
+
+ A CSS processor is considered to
+ support an at-rule
+ if it would accept an [=at-rule=] beginning with the specified at-keyword
+ within any context.
+
+ Note: Because ''@charset'' is not a valid [=at-rule=],
+ it is not considered to be supported under this definition.
+
Generalized Conditional Rules: the ''@when'' rule
@@ -1812,6 +1839,14 @@ Changes since the #10544)
+
+ Extended [=supports queries=] to express [=at-rule=] capabilities
+ via ''at-rule()''.
+ (#2463,
+ #6966,
+ #11116,
+ #11117)
+
@@ -1849,6 +1884,8 @@ Additions since Level 4
Added ''@when'' and ''@else''.
Extended [=supports queries=] to express font capabilities
via ''font-tech()'' and ''font-format()''.
+ Extended [=supports queries=] to express at-rule capabilities
+ via ''at-rule()''.
Moved Container Queries from [[CSS-CONTAIN-3]] to this specification.
(See also the [[CSS-CONTAIN-3#changes]] for more information
on the evolution of this feature.)