In addition to what we’ve covered, CSS2 adds a small number of new units, almost all of which are concerned with aural style sheets (employed by those browsers that are capable of speech). We’ll briefly cover them here:
Used to define
the position from which a given sound should seem to originate. There
are three type of angles: degrees (
deg ), grads
grad ), and radians (
For example, a right angle could be declared as
100grad , or
1.57rad ; in each case, the values are translated
into degrees in the range 0
through 360. This is also true of negative values, which are allowed.
-90deg is the same as
Used to specify
delays between speaking elements, these values can be expressed as
either milliseconds (
ms) or seconds
0.1s are equivalent. Time values may not be
declare a given frequency for the sounds that speaking browsers can
produce. Frequency values can be expressed as hertz
Hz) or megahertz (
cannot be negative. The values labels are case-insensitive, so
10mhz are equivalent.
In addition to these values, there is also an old friend with a new
Identifier, which is sort of another name for a Uniform Resource Locator (URL). The difference is, for now, mostly semantic, but many authors are beginning to adopt the convention of referring to online addresses as URIs, not URLs. The specification still requires ...