max-height - CSS: Cascading Style Sheets 编辑

The max-height CSS property sets the maximum height of an element. It prevents the used value of the height property from becoming larger than the value specified for max-height.

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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.

max-height overrides height, but min-height overrides max-height.

Syntax

/* <length> value */
max-height: 3.5em;

/* <percentage> value */
max-height: 75%;

/* Keyword values */
max-height: none;
max-height: max-content;
max-height: min-content;
max-height: fit-content(20em);

/* Global values */
max-height: inherit;
max-height: initial;
max-height: unset;

Values

<length>

Defines the max-height as an absolute value.

<percentage>

Defines the max-height as a percentage of the containing block's height.

none

No limit on the size of the box.

max-content

The intrinsic preferred max-height.

min-content

The intrinsic minimum max-height.

fit-content(<length-percentage>)

Uses the fit-content formula with the available space replaced by the specified argument, i.e. min(max-content, max(min-content, argument)).

Accessibility concerns

Ensure that elements set with a max-height are not truncated and/or do not obscure other content when the page is zoomed to increase text size.

• MDN Understanding WCAG, Guideline 1.4 explanations
• Understanding Success Criterion 1.4.4 | W3C Understanding WCAG 2.0

Formal definition

Initial value	none
Applies to	all elements but non-replaced inline elements, table columns, and column groups
Inherited	no
Percentages	The percentage is calculated with respect to the height of the generated box's containing block. If the height of the containing block is not specified explicitly (i.e., it depends on content height), and this element is not absolutely positioned, the percentage value is treated as none.
Computed value	the percentage as specified or the absolute length or none
Animation type	a length, percentage or calc();

Formal syntax

none | <length-percentage> | min-content | max-content | fit-content(<length-percentage>)
where 
<length-percentage> = <length> | <percentage>

Examples

Setting max-height using percentage and keyword values

table { max-height: 75%; }

form { max-height: none; }

Specifications

Specification	Status	Comment
CSS Box Sizing Module Level 4 The definition of 'max-height' in that specification.	Editor's Draft
CSS Box Sizing Module Level 3 The definition of 'max-height' in that specification.	Working Draft	Adds the max-content, min-content, fit-content keywords.
CSS Level 2 (Revision 1) The definition of 'max-height' in that specification.	Recommendation	Initial definition.

Browser compatibility

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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.

See also

• The box model, box-sizing
• height, min-height
• The mapped logical properties: max-inline-size, max-block-size