非常教程

CSS参考手册

基本用户界面 | Basic User Interface

轮廓 | outline

CSS的outline属性是用来设置一个或多个单独的轮廓属性的简写属性 , 例如 outline-style,outline-widthoutline-color。 多数情况下,简写属性更加可取和便捷。

/* width | style | color */
outline: 1px solid white;

/* Global values */
outline: inherit;
outline: initial;
outline: unset;

轮廓与边框在以下几个方面存在不同:

  • 轮廓不占据空间,它们被描绘于内容之上

  • 轮廓可以是非矩形的。在Gecko/Firefox中,轮廓是矩形的,但是Opera则会围绕元素结构绘制非矩形的形状,如下图

TEXTTEXTEXT

初始值

as each of the properties of the shorthand: outline-color: invert, for browsers supporting it, currentColor for the other outline-style: none outline-width: medium

适用元素

all elements

是否是继承属性

no

适用媒体

visual, interactive

计算值

as each of the properties of the shorthand: outline-color: For the keyword invert, the computed value is invert. For the color value, 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). outline-width: an absolute length; if the keyword none is specified, the computed value is 0 outline-style: as specified

Animation type

as each of the properties of the shorthand: outline-color: a color outline-width: a length outline-style: discrete

正规顺序

order of appearance in the formal grammar of the values

  • outline-colorinvert,对于支持它的浏览器,currentColor为另一个
  • outline-stylenone
  • outline-widthmedium
Applies to all elements   [Inherited](inheritance) no   Media visual, interactive   [Computed value](computed_value) as each of the properties of the shorthand:
  • outline-color:对于关键字invert,计算值是invert。对于颜色值,如果该值是半透明的,则计算的值将是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)
  • outline-width:绝对长度; 如果none指定关键字,则计算的值为0
  • outline-style:具体规定
Animation type as each of the properties of the shorthand:
  • outline-color:颜色
  • outline-width:长度
  • outline-style:离散
Canonical order order of appearance in the formal grammar of the values  

语法

outline属性被指定为下面列表中的一个,两个或三个值。值的顺序无关紧要。

outline-width设置轮廓的粗细。outline-style设置轮廓的样式。outline-color设置轮廓的颜色。由于Gecko 1.9(Firefox 3),元素color属性(前景色)的值被用作默认值。

正式语法

[ <'outline-color'> || <'outline-style'> || <'outline-width'> ]

示例

outline: solid; | outline: dashed red; | outline: dotted 1px; | outline: ridge thick violet; | outline: custom 5px;

/* Two identical declarations */

:link:hover { outline: 1px solid #000; }
:link:hover { outline: solid black 1px; }

规范

Specification

Status

Comment

CSS Basic User Interface Module Level 3The definition of 'outline' in that specification.

Candidate Recommendation

No change.

CSS Level 2 (Revision 1)The definition of 'outline' 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)

1.5 (1.8)1

8.0

7.0

1.2 (125)

Feature

Android

Edge

Firefox Mobile (Gecko)

IE Phone

Opera Mobile

Safari Mobile

Basic support

1.0

(Yes)

1.0 (1.8) 1

8.0

6.0

3.1

CSS

层叠样式表( Cascading Style Sheets )是一种用来表现 HTML 或 XML 等文件样式的计算机语言。CSS 不仅可以静态地修饰网页,还可以配合各种脚本语言动态地对网页各元素进行格式化。

CSS目录

1.动画和转换 | Animations & Transitions
2.背景和边框 | Backgrounds & Borders
3.基本框模型 | Basic Box Model
4.基本用户界面 | Basic User Interface
5.框对齐 | Box Alignment
6. 级联和继承 | Cascading & Inheritance
7.颜色 | Color
8. 合成与混合 | Compositing & Blending
9.条件和规则 | Conditional Rules
10.计数器样式 | Counter Styles
11.设备适配 | Device Adaptation
12.扩展 | Extensions
13.滤镜效果 | Filter Effects
14.灵活的框布局 | Flexible Box Layout
15.字体 | Fonts
16.片段模块 | Fragmentation
17.全屏 API | Fullscreen API
18. 生成内容 | Generated Content
19.网格布局 | Grid Layout
20.图像值 | Image Values
21.初始线格局 | Inline Layout
22.列表和计数器 | Lists & Counters
23.逻辑属性 | Logical Properties
24.面具 | Masking
25.媒体查询 | Media Queries
26.杂项 | Miscellaneous
27.Miscellaneous Level 1
28.Miscellaneous Level 2
29.运动路径 | Motion Path
30. 多列布局 | Multi-column Layout
31.命名空间 | Namespaces
32.项目模型 | Object Model View
33.网页媒体 | Paged Media
34.定位布局 | Positioned Layout
35.伪元素 | Pseudo-
36.节奏大小 | Rhythmic Sizing
37. Ruby布局 | Ruby Layout
38.可缩放矢量图形 | Scalable Vector Graphics
39.滚动快照 | Scroll Snap
40.选择 | Selectors
41.形状 | Shapes
42.文本 | Text
43.文字装饰 | Text Decoration
44.变换 | Transforms
45.值和单位 | Values & Units
46.变量 | Variables
47.写入模型 | Writing Modes
48.CSS 教程
49.CSS 创建
50.CSS Id 和 Class选择器
51.CSS 简介
52.CSS 盒子模型
53.CSS Table(表格)
54.CSS 列表样式(ul)
55.CSS 链接(link)
56.CSS Fonts(字体)
57.CSS Text(文本)
58.CSS Backgrounds(背景)
59.CSS Display(显示) 与 Visibility(可见性)
60.CSS 尺寸 (Dimension)
61.CSS 分组和嵌套
62.CSS 轮廓(outline)属性
63.CSS Border(边框)
64.CSS 图像透明/不透明
65.CSS 导航栏
66.CSS 伪元素
67.CSS 伪类
68.CSS Float(浮动)
69.CSS Position(定位)
70.CSS 总结
71.CSS 属性选择器
72.CSS 媒体类型
73.CSS 图像拼合技术
74.CSS 实例
75.CSS 组合选择符
76.响应式 Web 设计 – 框架
77.响应式 Web 设计 – 视频(Video)
78.CSS 提示工具(Tooltip)
79.CSS 布局 Overflow
80.CSS 计数器
81.CSS 表单