break-inside - CSS: Cascading Style Sheets 编辑

The break-inside CSS property sets how page, column, or region breaks should behave inside a generated box. If there is no generated box, the property is ignored.

/* Keyword values */
break-inside: auto;
break-inside: avoid;
break-inside: avoid-page;
break-inside: avoid-column;
break-inside: avoid-region;

/* Global values */
break-inside: inherit;
break-inside: initial;
break-inside: unset;

Each possible break point (in other words, each element boundary) is affected by three properties: the break-after value of the previous element, the break-before value of the next element, and the break-inside value of the containing element.

To determine if a break must be done, the following rules are applied:

1. If any of the three concerned values is a forced break value (always, left, right, page, column, or region), it has precedence. If more than one of them are such a break, the value of the element that appears the latest in the flow is used. Thus, the break-before value has precedence over the break-after value, which in turn has precedence over the break-inside value.
2. If any of the three concerned values is an avoid break value (avoid, avoid-page, avoid-region, or avoid-column), no such break will be applied at that point.

Once forced breaks have been applied, soft breaks may be added if needed, but not on element boundaries that resolve in a corresponding avoid value.

Syntax

The break-inside property is specified as one of the keyword values from the list below.

Values

auto

Allows, but does not force, any break (page, column, or region) to be inserted within the principal box.

avoid

Avoids any break (page, column, or region) from being inserted within the principal box.

avoid-page

Avoids any page break within the principal box.

avoid-column

Avoids any column break within the principal box.

avoid-region

Avoids any region break within the principal box.

Page break aliases

For compatibility reasons, the legacy page-break-inside property should be treated by browsers as an alias of break-inside. This ensures that sites using page-break-inside continue to work as designed. A subset of values should be aliased as follows:

Formal definition

Formal syntax

auto | avoid | avoid-page | avoid-column | avoid-region

Examples

Avoiding breaking inside a figure

In the following example we have a container that contains an <h1> spanning all columns (achieved using column-span: all) and a series of paragraphs laid out in multiple columns using column-width: 200px. We also have a <figure> containing an image and a caption.

By default, it is possible for you to get a break between the image and its caption, which is not what we want. To avoid this, we have set break-inside: avoid on the <figure>, which causes them to always stay together.

HTML

<article>
  <h1>Main heading</h1>

  <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nulla vitae fringilla mauris. Quisque commodo eget nisi sed pretium. Mauris luctus nec lacus in ultricies. Mauris vitae hendrerit arcu, ac scelerisque lacus. Aliquam lobortis in lacus sit amet posuere. Fusce iaculis urna id neque dapibus, eu lacinia lectus dictum.</p>

  <figure>
    <img src="https://www.wenjiangs.com/wp-content/uploads/2020/mozilla/firefox.png">
    <figcaption>The Firefox logo — fox wrapped around the world</figcaption>
  </figure>

  <p>Praesent condimentum dui dui, sit amet rutrum diam tincidunt eu. Cras suscipit porta leo sit amet rutrum. Sed vehicula ornare tincidunt. Curabitur a ipsum ac diam mattis volutpat ac ut elit. Nullam luctus justo non vestibulum gravida. Morbi metus libero, pharetra non porttitor a, molestie nec nisi.</p>

  <p>In finibus viverra enim vel suscipit. Quisque consequat velit eu orci malesuada, ut interdum tortor molestie. Proin sed pellentesque augue. Nam risus justo, faucibus non porta a, congue vel massa. Cras luctus lacus nisl, sed tincidunt velit pharetra ac. Duis suscipit faucibus dui sed ultricies.</p>
</article>

CSS

html {
  font-family: helvetica, arial, sans-serif;
}

body {
  width: 80%;
  margin: 0 auto;
}

h1 {
  font-size: 3rem;
  letter-spacing: 2px;
  column-span: all;
}

h1 + p {
  margin-top: 0;
}

p {
  line-height: 1.5;
  break-after: column;
}

figure {
  break-inside: avoid;
}

img {
  max-width: 70%;
  display: block;
  margin: 0 auto;
}

figcaption {
  font-style: italic;
  font-size: 0.8rem;
  width: 70%;
}

article {
  column-width: 200px;
  gap: 20px;
}

Result

Specifications

Browser compatibility

BCD tables only load in the browser

Notes on compatibility

Prior to Firefox 65, the older property of page-break-inside will work in Firefox to prevent breaks in columns, as well as pages. Add both properties for backwards compatibility.

For older WebKit-based browsers, the prefixed property -webkit-column-break-inside can be used to control column breaks.

See also

• Multiple-column Layout
• Breaking Boxes With CSS Fragmentation