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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.

The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

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.

句法 

/* <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;

margin-left property is specified as the keyword auto ，或 <length> ，或 <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 width 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 注释
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 ，或 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

形式定义

初始值 0
适用于 all elements, except elements with table display types other than table-caption , table and inline-table . It also applies to ::first-letter and ::first-line .
继承 no
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 a length

形式句法 

<length> | <percentage> | auto

范例

Setting left margin using pixels and percentages 

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

规范

规范 状态 注释
CSS 基本 Box 模型
The definition of 'margin-left' in that specification. 		工作草案 No significant change from CSS 2.1.
CSS Flexible Box Layout Module
The definition of 'margin-left' in that specification. 		候选推荐 Defines the behavior of margin-left on flex items.
CSS Level 2 (Revision 1)
The definition of 'margin-left' in that specification. 		推荐 Like in CSS1, but removes its effect on inline elements.
CSS Level 1
The definition of 'margin-left' in that specification. 		推荐 初始定义。

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据
Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet
margin-left Chrome 完整支持 1 Edge 完整支持 12 Firefox 完整支持 1 IE 完整支持 3 Opera 完整支持 3.5 Safari 完整支持 1 WebView Android 完整支持 1 Chrome Android 完整支持 18 Firefox Android 完整支持 4 Opera Android 完整支持 10.1 Safari iOS 完整支持 1 Samsung Internet Android 完整支持 1.0
auto Chrome 完整支持 1 Edge 完整支持 12 注意事项
完整支持 12 注意事项
注意事项 auto value is not supported in quirks mode.
Firefox 完整支持 1 IE 完整支持 6 注意事项
完整支持 6 注意事项
注意事项 auto value is not supported in quirks mode.
Opera 完整支持 3.5 Safari 完整支持 1 WebView Android 完整支持 37 Chrome Android 完整支持 18 Firefox Android 完整支持 4 Opera Android 完整支持 14 Safari iOS 完整支持 1 Samsung Internet Android 完整支持 1.0

图例

完整支持

完整支持

见实现注意事项。

见实现注意事项。

另请参阅

元数据

  • 最后修改：
  1. CSS
  2. CSS 参考
  3. CSS Box Model
  4. 指南
    1. CSS 基本 Box 模型介绍
    2. Mastering margin collapsing
  5. 特性
    1. height
    2. margin-bottom
    3. margin-left
    4. margin-right
    5. margin-top
    6. margin-trim
    7. max-height
    8. max-width
    9. min-height
    10. min-width
    11. overscroll-behavior
    12. overscroll-behavior-block
    13. overscroll-behavior-inline
    14. overscroll-behavior-x
    15. overscroll-behavior-y
    16. padding
    17. padding-bottom
    18. padding-left
    19. padding-right
    20. padding-top
    21. visibility
    22. width