填充顶部 | padding-top

padding-top

CSS属性padding-top 是指一个元素在内边距区域（padding area）中上方的高度。内边距（padding）是指一个元素的内容和边框之间的区域。和外边距（margin）不同，内边距（padding）是不允许有负值的。内边距（padding）可以用四个值声明一个元素的四个方向的内边距（paddings），这是一种CSS缩写属性。

/* <length> values */
padding-top: 0.5em;
padding-top: 0;
padding-top: 2cm;

/* <percentage> value */
padding-top: 10%;

/* Global values */
padding-top: inherit;
padding-top: initial;
padding-top: unset;

元素的填充区域是其内容和边界之间的空间。

初始值	0
适用元素	all elements, except table-row-group, table-header-group, table-footer-group, table-row, table-column-group and table-column. It also applies to ::first-letter.
是否是继承属性	no
Percentages	refer to the width of the containing block
适用媒体	visual
计算值	the percentage as specified or the absolute length
Animation type	a length
正规顺序	the unique non-ambiguous order defined by the formal grammar

语法

值

length当内边距（padding）大小是一个固定单位数值的时候，一定不能为负数。percentage当内边距（padding）是一个百分比的时候，百分比是和父元素的宽度有关的，同样一定不能为负数。

正式语法

<length> | <percentage>

示例

.content { padding-top: 5%; }
.sidebox { padding-top: 10px; }

规范

Specification	Status	Comment
CSS Basic Box ModelThe definition of 'padding-top' in that specification.	Working Draft	No change from CSS Level 2 (Revision 1)The definition of 'padding-top' in that specification..
CSS TransitionsThe definition of 'padding-top' in that specification.	Working Draft	Defines padding-top as animatable.
CSS Level 2 (Revision 1)The definition of 'padding-top' in that specification.	Recommendation	No change from CSS Level 1The definition of 'padding-top' in that specification..
CSS Level 1The definition of 'padding-top' in that specification.	Recommendation	Initial definition.

浏览器兼容性

Feature	Chrome	Edge	Firefox (Gecko)	Internet Explorer	Opera	Safari (WebKit)
Basic support	1.0	(Yes)	1.0 (1.0)	4.0	3.5	1.0 (85)

Feature	Android	Edge	Firefox Mobile (Gecko)	IE Phone	Opera Mobile	Safari Mobile
Basic support	?	(Yes)	?	?	?	?