边界块启动 | border-block-start

这是一项实验技术

由于该技术的规格不稳定，请查看兼容性表以了解各种浏览器的使用情况。还请注意，随着规范的变化，实验技术的语法和行为在未来版本的浏览器中可能会发生变化。

border-block-start CSS 属性是在样式表一个单一的地方设置单独的逻辑块开始 border 属性值的速记属性。

border-block-start: 1px;
border-block-start: 2px dotted;
border-block-start: medium dashed blue;

border-block-start可用于对一个或多个的设置的值border-block-start-width，border-block-start-style和border-block-start-color。它映射的物理边界取决于元素的写入模式，方向性和文本方向。它对应于border-top，border-right，border-bottom，或border-left属性根据为定义的值writing-mode，direction和text-orientation。

相关属性是border-block-end，border-inline-start和border-inline-end，它们定义了元素的其他边界。

Initial value	as each of the properties of the shorthand: border-width: as each of the properties of the shorthand: border-top-width: medium border-right-width: medium border-bottom-width: medium border-left-width: medium border-style: as each of the properties of the shorthand: border-top-style: none border-right-style: none border-bottom-style: none border-left-style: none color: Varies from one browser to another
Applies to	all elements
Inherited	no
Media	visual
Computed value	as each of the properties of the shorthand: border-width: as each of the properties of the shorthand: border-bottom-width: the absolute length or 0 if border-bottom-style is none or hidden border-left-width: the absolute length or 0 if border-left-style is none or hidden border-right-width: the absolute length or 0 if border-right-style is none or hidden border-top-width: the absolute length or 0 if border-top-style is none or hidden border-style: as each of the properties of the shorthand: border-bottom-style: as specified border-left-style: as specified border-right-style: as specified border-top-style: as specified color: If the value is translucent, the computed value will be the rgba() corresponding one. If it isn't, it will be the rgb() corresponding one. The transparent keyword maps to rgba(0,0,0,0).
Animation type	discrete
Canonical order	the unique non-ambiguous order defined by the formal grammar

border-width：作为速记的每个属性：

-  [`border-top-width`](border-top-width): `medium` 
-  [`border-right-width`](border-right-width): `medium` 
-  [`border-bottom-width`](border-bottom-width): `medium` 
-  [`border-left-width`](border-left-width): `medium`

border-style：作为速记的每个属性：

-  [`border-top-style`](border-top-style): `none` 
-  [`border-right-style`](border-right-style): `none` 
-  [`border-bottom-style`](border-bottom-style): `none` 
-  [`border-left-style`](border-left-style): `none`

color：因浏览器而异

Applies to all elements   [Inherited](inheritance) no   Media visual   [Computed value](computed_value) as each of the properties of the shorthand:

border-width：作为速记的每个属性：

-  [`border-bottom-width`](border-bottom-width): the absolute length or `0` if [`border-bottom-style`](border-bottom-style) is `none` or `hidden` 
-  [`border-left-width`](border-left-width): the absolute length or `0` if [`border-left-style`](border-left-style) is `none` or `hidden` 
-  [`border-right-width`](border-right-width): the absolute length or `0` if [`border-right-style`](border-right-style) is `none` or `hidden` 
-  [`border-top-width`](border-top-width): the absolute length or `0` if [`border-top-style`](border-top-style) is `none` or `hidden`

border-style：作为速记的每个属性：

-  [`border-bottom-style`](border-bottom-style): as specified
-  [`border-left-style`](border-left-style): as specified
-  [`border-right-style`](border-right-style): as specified
-  [`border-top-style`](border-top-style): as specified

color：如果该值是半透明的，则计算出的值将是rgba()相应的值。如果不是，那将是rgb()相应的一个。该transparent关键字映射到rgba(0,0,0,0)。

Animation type discrete   Canonical order the unique non-ambiguous order defined by the formal grammar

语法

值

在border-block-start与一个或多个以下的规定，以任何顺序：

<'border-width'>边框的宽度。看border-width。

<'border-style'>边框的线条样式。看border-style。

<'color'>边框的颜色。看color。

形式语法

<'border-width'> || <'border-style'> || <'color'>where <color> = <rgb()> | <rgba()> | <hsl()> | <hsla()> | <hex-color> | <named-color> | currentcolor | <deprecated-system-color>where <rgb()> = rgb( [ [ <percentage>{3} | <number>{3} ] [ / <alpha-value> ]? ] | [ [ <percentage>#{3} | <number>#{3} ] , <alpha-value>? ] )<rgba()> = rgba( [ [ <percentage>{3} | <number>{3} ] [ / <alpha-value> ]? ] | [ [ <percentage>#{3} | <number>#{3} ] , <alpha-value>? ] )<hsl()> = hsl( [ <hue> <percentage> <percentage> [ / <alpha-value> ]? ] | [ <hue>, <percentage>, <percentage>, <alpha-value>? ] )<hsla()> = hsla( [ <hue> <percentage> <percentage> [ / <alpha-value> ]? ] | [ <hue>, <percentage>, <percentage>, <alpha-value>? ] )where <alpha-value> = <number> | <percentage><hue> = <number> | <angle>

例子

HTML 内容

<div>
  <p class="exampleText">Example text</p>
</div>

CSS 内容

div {
  background-color: yellow;
  width: 120px;
  height: 120px;
}

.exampleText {
  writing-mode: vertical-rl;
  border-block-start: 5px dashed blue;
}

规范

Specification	Status	Comment
CSS Logical Properties Level 1The definition of 'border-block-start' in that specification.	Editor's Draft	Initial definition

浏览器兼容性

Feature	Chrome	Firefox (Gecko)	Internet Explorer	Opera	Safari (WebKit)
Basic support	No support	41.0 (41.0)1	No support	No support	No support

Feature	Android	Firefox Mobile (Gecko)	IE Phone	Opera Mobile	Safari Mobile
Basic support	No support	41.0 (41.0)1	No support	No support	No support

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最后更新于：2017-12-18