非常教程

CSS参考手册

基本框模型 | Basic Box Model

左边距 | margin-left

margin-left  属性 设置与元素相关联的盒子模型的左外边距。这个值可以为负值。

/* <length> values */
margin-left: 10px;  /* An absolute length */
margin-left: 1em;   /* relative to the text size */
margin-left: 5%;    /* relative to the nearest block container's width */

/* Keyword values */
margin-left: auto;

/* Global values */
margin-left: inherit;
margin-left: initial;
margin-left: unset;

竖直排列相邻的两个盒子模型的外边距会重叠 margin collapsing

在长度(width)被约束这种极少情况下,( 即当所有的宽度,左边界,边界,填充内容区域和边缘都被定义), 左边界会被忽略,如果被制定为auto值,会有相同的计算值。

初始值

0

适用元素

all elements, except elements with table display types other than table-caption, table and inline-table. 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

margin-left属性被指定为关键字auto,或a <length>或a <percentage>。它的值可以是正值,零值或负值。

<length>一个固定宽度 <length> 值 : 可以是一个绝对宽度, e.g. inpx, 也可以是个相对宽度, e.g. inem, 或者相对视窗的大小, e.g. invh.<percentage>百分比值<percentage>最近的块容器的宽度 width.autoauto关键词表示在当前布局模式下,浏览器根据接收的左边距自动计算出外边距。如果有几组margin-left和margin-right 设置为auto,那么最后计算的空间分布,会根据display,float,position属性,自动生成以下几种情况:

Value of display

Value of float

Value of position

Computed value of auto

Comment

inline, inline-block, inline-table

any

static or relative

0

Inline layout mode

block, inline, inline-block, block, table, inline-table, list-item, table-caption

any

static or relative

0, 除非margin-left和   margin-right同时都设置为auto. 这样的话,元素就被设置为基于父元素居中。

Block layout mode

block, inline, inline-block, block, table, inline-table, list-item, table-caption

left or right

static or relative

0

Block layout mode (floating element)

any table-*, except table-caption

any

any

0

Internal table-* elements don't have margins, use border-spacing instead

any, except flex, inline-flex, or table-*

any

fixed or absolute

0, except if both margin-left and margin-right are set to auto. In this case, it is set to the value centering the border area inside the available width, if fixed.

Absolutely positioned layout mode

flex, inline-flex

any

any

0, except if there is any positive horizontal free space. In this case, it is evenly distributed to all horizontal auto margins.

Flexbox layout mode

正式语法

<length> | <percentage> | auto

示例

.content { margin-left: 5%; }
.sidebox { margin-left: 10px; }
.logo    { margin-left: -5px; }

规范

Specification

Status

Comment

CSS Basic Box ModelThe definition of 'margin-left' in that specification.

Working Draft

No significant change from CSS 2.1.

CSS TransitionsThe definition of 'margin-left' in that specification.

Working Draft

Defines margin-left as animatable.

CSS Flexible Box Layout ModuleThe definition of 'margin-left' in that specification.

Candidate Recommendation

Defines the behavior of margin-left on flex items.

CSS Level 2 (Revision 1)The definition of 'margin-left' in that specification.

Recommendation

Like in CSS1, but removes its effect on inline elements.

CSS Level 1The definition of 'margin-left' in that specification.

Recommendation

Initial definition.

Browser compatibility

Feature

Chrome

Edge

Firefox (Gecko)

Internet Explorer

Opera

Safari (WebKit)

Basic support

1.0

(Yes)

1.0 (1.7 or earlier)

3.0

3.5

1.0 (85)

auto value

1.0

(Yes)

1.0 (1.7 or earlier)

6.0 (strict mode)

3.5

1.0 (85)

Feature

Android

Edge

Firefox Mobile (Gecko)

IE Phone

Opera Mobile

Safari Mobile

Basic support

1.0

(Yes)

1.0 (1)

6.0

6.0

1.0

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