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MDN / counter() CSS function

The counter() CSS function returns a string representing the current value of the named counter, if there is one.

The counter() function is generally used within pseudo-element through the property but, theoretically, it can be used wherever a value is supported.

.double-list {
  counter-reset: count -1;
}

.double-list li {
  counter-increment: count 2;
}

.double-list li::marker {
  content: counter(count, decimal) ") ";
}

<p>Best Dynamic Duos in Sports:</p>
<ol class="double-list">
  <li>Simone Biles + Jonathan Owens</li>
  <li>Serena Williams + Venus Williams</li>
  <li>Aaron Judge + Giancarlo Stanton</li>
  <li>LeBron James + Dwyane Wade</li>
  <li>Xavi Hernandez + Andres Iniesta</li>
</ol>

Syntax

/* Basic usage */
counter(counter-name);

/* changing the counter display */
counter(counter-name, upper-roman)

Counters have no visible effect by themselves. The counter() and functions are what make counters useful by returning developer-defined strings (or images).

Values

The counter() function accepts up to two parameters. The first parameter is the <counter-name>. The optional second parameter is the <counter-style>.

  • <counter-name>

    • : A identifying the counter, which is the same case-sensitive name used with the and property values. The counter name cannot start with two dashes and can’t be none, unset, initial, or inherit.

    <counter-style>

    • : A name, or function, where a counter style name is a numeric, alphabetic, or symbolic predefined counter style, a complex longhand east Asian or Ethiopic predefined counter style, or other predefined counter style. If omitted, the counter-style defaults to decimal.

To join the counter values when nesting counters, use the function, which provides an additional parameter.

Formal syntax

Examples

lower-roman compared to lower-alpha

In this example, we display a counter using lower-roman and lower-alpha list styles.

HTML

<ol>
  <li></li>
  <li></li>
  <li></li>
</ol>

CSS

ol {
  counter-reset: count;
}
li {
  counter-increment: count;
}
li::after {
  content:
    "[" counter(count, lower-roman) "] == ["
    counter(count, lower-alpha) "]";
}

Result

Displaying a counter using three styles

In this example, we use the counter() function three times.

HTML

<ol>
  <li></li>
  <li></li>
  <li></li>
</ol>

CSS

We include the counter() function with three different counter styles, including the default decimal value. We’ve added padding to the list to provide space for the long ::marker string.

ol {
  counter-reset: listCounter;
  padding-left: 5em;
}
li {
  counter-increment: listCounter;
}
li::marker {
  content:
    "Item #" counter(listCounter) " is: ";
}
li::after {
  content:
    "[" counter(listCounter, decimal-leading-zero) "] == ["
    counter(listCounter, upper-roman) "]";
}

Result

Specifications

Browser compatibility

See also