computed value of a CSS property is the value that is transferred from parent to child during inheritance. It is calculated from the specified value by:
inherit
,
initial
,
unset
，和
revert
.
The computation needed to reach a property's computed value typically involves converting relative values (such as those in
em
units or percentages) to absolute values. For example, if an element has specified values
font-size: 16px
and
padding-top: 2em
, then the computed value of
padding-top
is
32px
(double the font size).
However, for some properties (those where percentages are relative to something that may require layout to determine, such as
width
,
margin-right
,
text-indent
，和
top
), percentage-specified values turn into percentage-computed values. Additionally, unitless numbers specified on the
line-height
property become the computed value, as specified. The relative values that remain in the computed value become absolute when the
used value
is determined.
注意：
getComputedStyle()
DOM API returns the
resolved value
, which may either be the
computed value
或
used value
, depending on the property.
| 规范 | 状态 | 注释 |
|---|---|---|
|
CSS Level 2 (Revision 2)
The definition of 'computed-value' in that specification. |
工作草案 | 无变化。 |
|
CSS Level 2 (Revision 1)
The definition of 'computed value' in that specification. |
推荐 | 初始定义。 |
window.getComputedStyle