:nth-last-child() - CSS: Cascading Style Sheets 编辑

The :nth-last-child() CSS pseudo-class matches elements based on their position among a group of siblings, counting from the end.

/* Selects every fourth element
   among any group of siblings,
   counting backwards from the last one */
:nth-last-child(4n) {
  color: lime;
}

Note: This pseudo-class is essentially the same as :nth-child, except it counts items backwards from the end, not forwards from the beginning.

Syntax

The nth-last-child pseudo-class is specified with a single argument, which represents the pattern for matching elements, counting from the end.

Keyword values

odd

Represents elements whose numeric position in a series of siblings is odd: 1, 3, 5, etc., counting from the end.

even

Represents elements whose numeric position in a series of siblings is even: 2, 4, 6, etc., counting from the end.

Functional notation

<An+B>

Represents elements whose numeric position in a series of siblings matches the pattern An+B, for every positive integer or zero value of n. The index of the first element, counting from the end, is 1. The values A and B must both be <integer>s.

Formal syntax

:nth-last-child( <nth> [ of <complex-selector-list> ]? )
where 
<nth> = <an-plus-b> | even | odd
<complex-selector-list> = <complex-selector>#
where 
<complex-selector> = <compound-selector> [ <combinator>? <compound-selector> ]*
where 
<compound-selector> = [ <type-selector>? <subclass-selector>* [ <pseudo-element-selector> <pseudo-class-selector>* ]* ]!
<combinator> = '>' | '+' | '~' | [ '||' ]
where 
<type-selector> = <wq-name> | <ns-prefix>? '*'
<subclass-selector> = <id-selector> | <class-selector> | <attribute-selector> | <pseudo-class-selector>
<pseudo-element-selector> = ':' <pseudo-class-selector>
<pseudo-class-selector> = ':' <ident-token> | ':' <function-token> <any-value> ')'
where 
<wq-name> = <ns-prefix>? <ident-token>
<ns-prefix> = [ <ident-token> | '*' ]?  | 
<id-selector> = <hash-token>
<class-selector> = '.' <ident-token>
<attribute-selector> = '[' <wq-name> ']' | '[' <wq-name> <attr-matcher> [ <string-token> | <ident-token> ] <attr-modifier>? ']'
where 
<attr-matcher> = [ '~' |  |  | '^' | '$' | '*' ]? '='
<attr-modifier> = i | s

Examples

Example selectors

tr:nth-last-child(odd) or tr:nth-last-child(2n+1)

Represents the odd rows of an HTML table: 1, 3, 5, etc., counting from the end.

tr:nth-last-child(even) or tr:nth-last-child(2n)

Represents the even rows of an HTML table: 2, 4, 6, etc., counting from the end.

:nth-last-child(7)

Represents the seventh element, counting from the end.

:nth-last-child(5n)

Represents elements 5, 10, 15, etc., counting from the end.

:nth-last-child(3n+4)

Represents elements 4, 7, 10, 13, etc., counting from the end.

:nth-last-child(-n+3)

Represents the last three elements among a group of siblings.

p:nth-last-child(n) or p:nth-last-child(n+1)

Represents every <p> element among a group of siblings. This is the same as a simple p selector. (Since n starts at zero, while the last element begins at one, n and n+1 will both select the same elements.)

p:nth-last-child(1) or p:nth-last-child(0n+1)

Represents every <p> that is the first element among a group of siblings, counting from the end. This is the same as the :last-child selector.

Table example

HTML

<table>
  <tbody>
    <tr>
      <td>First line</td>
    </tr>
    <tr>
      <td>Second line</td>
    </tr>
    <tr>
      <td>Third line</td>
    </tr>
    <tr>
      <td>Fourth line</td>
    </tr>
    <tr>
      <td>Fifth line</td>
    </tr>
  </tbody>
</table>

CSS

table {
  border: 1px solid blue;
}

/* Selects the last three elements */
tr:nth-last-child(-n+3) {
  background-color: pink;
}

/* Selects every element starting from the second to last item */
tr:nth-last-child(n+2) {
  color: blue;
}

/* Select only the last second element */
tr:nth-last-child(2) {
  font-weight: 600;
}

Result

Quantity query

A quantity query styles elements depending on how many of them there are. In this example, list items turn red when there are at least three of them in a given list. This is accomplished by combining the capabilities of the nth-last-child pseudo-class and the general sibling combinator.

HTML

<h4>A list of four items (styled):</h4>
<ol>
  <li>One</li>
  <li>Two</li>
  <li>Three</li>
  <li>Four</li>
</ol>

<h4>A list of two items (unstyled):</h4>
<ol>
  <li>One</li>
  <li>Two</li>
</ol>

CSS

/* If there are at least three list items,
   style them all */
li:nth-last-child(n+3),
li:nth-last-child(n+3) ~ li {
  color: red;
}

Result

Specifications

Browser compatibility

BCD tables only load in the browser

See also

• :nth-child, :nth-last-of-type
• Quantity Queries for CSS