margin-left

The margin-left CSS property sets the margin area on the left side of an element. A positive value places it farther from its neighbors, while a negative value places it closer.

试一下

The vertical margins of two adjacent boxes may fuse. This is called margin collapsing.

In the rare cases where width is overconstrained (i.e., when all of width, margin-left, border, padding, the content area, and margin-right are defined), margin-left is ignored, and will have the same calculated value as if the auto value was specified.

语法

css
/* <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: revert;
margin-left: revert-layer;
margin-left: unset;

The margin-left property is specified as the keyword auto, or a <length>, or a <percentage>. Its value can be positive, zero, or negative.

值

<length>

The size of the margin as a fixed value.

<percentage>

The size of the margin as a percentage, relative to the inline size (width in a horizontal language, defined by writing-mode) of the containing block.

auto

The left margin receives a share of the unused horizontal space, as determined mainly by the layout mode that is used. If the values of margin-left and margin-right are both auto, the calculated space is evenly distributed. This table summarizes the different cases

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, except if both margin-left and margin-right are set to auto. In this case, it is set to the value centering the element inside its parent. 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

正式定义

初始值0
适用于所有元素，除了具有表格 display 类型的元素，这些元素类型不是 table-caption、table 和 inline-table。它也适用于 ::first-letter.
继承否
百分比refer to the width of the containing block
计算值the percentage as specified or the absolute length
动画类型一个 长度

正式语法

margin-left = 
  <length-percentage>  |
  auto                 

<length-percentage> = 
  <length>      |
  <percentage>

示例

将 margin-left 设置为百分比

margin-left 的百分比值相对于容器的内联大小。

HTML

html
<p>
  A large rose-tree stood near the entrance of the garden: the roses growing on
  it were white, but there were three gardeners at it, busily painting them red.
</p>
<p class="example">
  Alice thought this a very curious thing, and she went nearer to watch them,
  and just as she came up to them she heard one of them say, "Look out now,
  Five! Don't go splashing paint over me like that!"
</p>
<p>
  "I couldn't help it," said Five, in a sulky tone; "Seven jogged my elbow."
</p>

CSS

css
.example {
  margin-left: 50%;
}

结果

规范

规范
CSS 盒模型模块级别 3
# margin-physical

浏览器兼容性

BCD 表格仅在浏览器中加载

另请参阅