HTML and CSS Reference
In-Depth Information
length
An optional sign (either + or -), immediately followed by a number
(with or without a decimal point), immediately followed by a two-
character unit identifier. For values of
0
, the unit identifier may be
omitted.
The unit identifiers
em
and
ex
refer to the overall height of the font
and to the height of the letter "x," respectively. The unit identifier
px
is equal to a single pixel on the display device. The unit identifi-
ers
in
,
cm
,
mm
,
pt
, and
pc
refer to inches, centimeters, millimeters,
points, and picas, respectively. There are 72.27 points in an inch
and 12 points in a pica.
number
An optional sign, immediately followed by a number (with or
without a decimal point).
percent
An optional sign, immediately followed by a number (with or
without a decimal point), immediately followed by a percent sign.
The actual value is computed as a percentage of some other ele-
ment property, usually the element's size.
shape
A shape keyword, followed by a parentheses-enclosed list of
comma-separated, shape-specific parameters. Currently, the only
supported shape keyword is
rect
, which expects four numeric para-
meters denoting the offsets of the top, right, bottom, and left edges
of the rectangle.
time
A numeric value followed by
s
or
ms
, designating a time in seconds
or in milliseconds.
