height

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

概要

高度(height) 的 CSS 屬性指定了元素內容區域的高度。content area 在元素的留白(padding)、邊框(border) 與 邊界(margin) 內。

min-height 與 max-height 的特性比 height 更重要。

預設值auto
Applies toall elements but non-replaced inline elements, table columns, and column groups
繼承與否no
PercentagesThe 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 value computes to auto. A percentage height on the root element is relative to the initial containing block.
Computed valuea percentage or auto or the absolute length
Animation typea length, percentage or calc();

語法

css
/* Keyword value */
height: auto;

/* <length> values */
height: 120px;
height: 10em;

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

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

值

<length>

查看 <length> 可用的單位。

<percentage>

<percentage> 相對於元素的塊狀高度。如果沒有指定塊狀元素的高度，預設值為 auto。用在 root 元素 (e.g. <html>) 上是相對於初始塊狀元素（即顯示器的尺寸）。

border-box

If present, the preceding <length> or <percentage> is applied to the element's border box.

content-box

<length> 或 <percentage> 是應用於元素的 content box.

auto

瀏覽器將計算並選擇指定元素的高度。

fill

Use the fill-available inline size or fill-available block size, as appropriate to the writing mode.

max-content

The intrinsic preferred height.

min-content

The intrinsic minimum height.

available

The containing block height minus vertical margin, border and padding.

fit-content

The larger of:

  • the intrinsic minimum height
  • the smaller of the intrinsic preferred height and the available height

正式語法

height = 
  auto                                      |
  <length-percentage [0,∞]>                 |
  min-content                               |
  max-content                               |
  fit-content( <length-percentage [0,∞]> )  |
  <calc-size()>                             |
  <anchor-size()>                           

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

<calc-size()> = 
  calc-size( <calc-size-basis> , <calc-sum> )  

<anchor-size()> = 
  anchor-size( [ <anchor-name> || <anchor-size> ]? , <length-percentage>? )  

<calc-size-basis> = 
  <intrinsic-size-keyword>  |
  <calc-size()>             |
  any                       |
  <calc-sum>                

<calc-sum> = 
  <calc-product> [ [ '+' | '-' ] <calc-product> ]*  

<anchor-name> = 
  <dashed-ident>  

<anchor-size> = 
  width        |
  height       |
  block        |
  inline       |
  self-block   |
  self-inline  

<calc-product> = 
  <calc-value> [ [ '*' | '/' ] <calc-value> ]*  

<calc-value> = 
  <number>        |
  <dimension>     |
  <percentage>    |
  <calc-keyword>  |
  ( <calc-sum> )  

<calc-keyword> = 
  e          |
  pi         |
  infinity   |
  -infinity  |
  NaN

範例

HTML

html
<div id="red">
  <span>I'm 50 pixels tall.</span>
</div>
<div id="green">
  <span>I'm 25 pixels tall.</span>
</div>
<div id="parent">
  <div id="child">
    <span>I'm half the height of my parent.</span>
  </div>
</div>

CSS

css
div {
  width: 250px;
  margin-bottom: 5px;
  border: 3px solid #999999;
}

#red {
  height: 50px;
}

#green {
  height: 25px;
}

#parent {
  height: 100px;
}

#child {
  height: 50%;
  width: 75%;
}

規格

Specification
CSS Box Sizing Module Level 3
# preferred-size-properties
CSS Box Sizing Module Level 4
# sizing-values

瀏覽器兼容性

BCD tables only load in the browser

See also