<frequency> CSS data types denotes a frequency dimension, like the pitch of a speaking voice. They consists of a
<number> immediately followed by the unit. Like for any CSS dimension, there is no space between the unit literal and the number.
The following units may be used:
Hzwhich represents a frequency in Hertz. E.g.
kHzwhich represents a frequency in kilohertz. E.g.
Even if all units represent the same time for the value
0, the unit may not be omitted in that case as it isn't a
0 is invalid and does not represent
0kHz. Though the units are case-insensitive in CSS, it is good practice to use a capital H for
kHz, as in the SI, Hertz being a family noun.
These are valid frequency values:
12Hz Positive integer. -456kHz Negative integer. 4.3Hz Non-integer. 14KhZ The unit is case-insensitive, though non-SI capitalization is not recommended. +0Hz Zero, with a leading + and the unit. -0kHz Zero, with a leading - and the unit (Though strange, this is an allowed value).
These are invalid frequency values:
12.0 This is a <number>, not an <frequency>, it must have a unit. 7 Hz No space is allowed between the <number> and the unit. 0 Zero values can be written without a unit only if there are <length> values, not <frequency>.
|CSS Values and Units Module Level 3||Candidate Recommendation|
This data type was initially introduced in CSS Level 2 for the now obsoleted aural media group, where it was used to define the pitch of the voice. This has been deprecated since then, but the
<frequency> data type has been reintroduced in CSS3, though no CSS property is using it at the moment.
|Feature||Chrome||Firefox (Gecko)||Internet Explorer||Opera||Safari|
|Basic support||Not supported||Not supported||Not supported||Not supported [*]||Not supported|
|Feature||Android||Firefox Mobile (Gecko)||IE Mobile||Opera Mobile||Safari Mobile|
|Basic support||Not supported||Not supported||Not supported||Not supported||Not supported|
[*] Some versions of Opera may have (partial) support for the obsolete aural media group, and through the pitch property support for the
<frequency> data type.