break-after CSS 属性描述在生成的盒子之后的页面，列或区域中断行为（换句话说，如何以及是否中断）。如果没有生成的盒子，则该属性将被忽略。

/* Generic break values */
break-after: auto;
break-after: avoid;
break-after: always;
break-after: all;

/* Page break values */
break-after: avoid-page;
break-after: page;
break-after: left;
break-after: right;
break-after: recto;
break-after: verso;

/* Column break values */
break-after: avoid-column;
break-after: column;

/* Region break values */
break-after: avoid-region;
break-after: region;

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

每个潜在的断点（亦即每个元素的边界）都受到三个属性的影响：上一个元素的 break-after 值、下一个元素的 break-before 值以及当前元素自身的 break-inside 值。

以下规则被用于判断中断是否必要：

  1. 如果上述三个属性中，如果任何一个的值属于“强制中断”值，那么这个属性将被优先应用，此处所称“强制中断”的值为： always、 left、 right、 page、 column 和 region。If several of the concerned values is such a break, the one of the element that appears the latest in the flow is taken (that is the {{cssxref("break-before")}} value has precedence over the break-after value, which itself has precedence over the {{cssxref("break-inside")}} value).
  2. If any of the three concerned values is an avoid break value, that is avoid, avoid-page, avoid-region, 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.

{{cssinfo}}

语法

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

属性值

Generic break values

  • auto
    • : Allows, but does not force, any break (page, column, or region) to be inserted right after the principal box.
  • avoid
    • : Avoids any break (page, column, or region) from being inserted right after the principal box.
  • always {{experimental_inline}}
    • : Forces a page break right after the principal box. The type of this break is that of the immediately-containing fragmentation context. If we are inside a multicol container then it would force a column break, inside paged media (but not inside a multicol container) a page break.
  • all {{experimental_inline}}
    • : Forces a page break right after the principal box. Breaking through all possible fragmentation contexts. So a break inside a multicol container, which was inside a page container would force a column and page break.

Page break values

  • avoid-page
    • : Avoids any page break right after the principal box.
  • page
    • : Forces a page break right after the principal box.
  • left
    • : Forces one or two page breaks right after the principal box, whichever will make the next page into a left page.
  • right
    • : Forces one or two page breaks right after the principal box, whichever will make the next page into a right page.
  • recto {{experimental_inline}}
    • : Forces one or two page breaks right after the principal box, whichever will make the next page into a recto page. (A recto page is a right page in a left-to-right spread or a left page in a right-to-left spread.)
  • verso {{experimental_inline}}
    • : Forces one or two page breaks right after the principal box, whichever will make the next page into a verso page. (A verso page is a left page in a left-to-right spread or a left right in a right-to-left spread.)

Column break values

  • avoid-column
    • : Avoids any column break right after the principal box.
  • column
    • : Forces a column break right after the principal box.

Region break values

  • avoid-region {{experimental_inline}}
    • : Avoids any region break right after the principal box.
  • region {{experimental_inline}}
    • : Forces a region break right after the principal box.

形式化语法

{{csssyntax}}

Page break aliases

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

page-break-after break-after
auto auto
left left
right right
avoid avoid
always page

[!NOTE] The always value of page-break-* was implemented by browsers as a page break, and not as a column break. Therefore the aliasing is to page, rather than the always value in the Level 4 spec.