:has()

:has(<relative-selector-list>) {
  /* ... */
}

If the :has() pseudo-class itself is not supported in a browser, the entire selector block will fail unless :has() is in a forgiving selector list, such as in :is() and :where().

The :has() pseudo-class cannot be nested within another :has(). This is because many pseudo-elements exist conditionally based on the styling of their ancestors and allowing these to be queried by :has() can introduce cyclic querying.

Pseudo-elements are also not valid selectors within :has() and pseudo-elements are not valid anchors for :has().

The :has() style declaration in the following example adjusts the spacing after <h1> headings if they are immediately followed by an <h2> heading.

HTML

<section>
  <article>
    <h1>Morning Times</h1>
    <p>
      Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod
      tempor incididunt ut labore et dolore magna aliqua.
    </p>
  </article>
  <article>
    <h1>Morning Times</h1>
    <h2>Delivering you news every morning</h2>
    <p>
      Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod
      tempor incididunt ut labore et dolore magna aliqua.
    </p>
  </article>
</section>

CSS

section {
  display: flex;
  align-items: start;
  justify-content: space-around;
}

article {
  display: inline-block;
  width: 40%;
}

h1,
h2 {
  font-size: 1.2em;
}

h2 {
  font-size: 1em;
  color: rgb(150 149 149);
}

h1,
h2 {
  margin: 0 0 1rem 0;
}

h1:has(+ h2) {
  margin: 0 0 0.25rem 0;
}

Result

This example shows two similar texts side-by-side for comparison – the left one with an H1 heading followed by a paragraph and the right one with an H1 heading followed by an H2 heading and then a paragraph. In the example on the right, :has() helps to select the H1 element that is immediately followed by an H2 element (indicated by the next-sibling combinator +) and the CSS rule reduces the spacing after such an H1 element. Without the :has() pseudo-class, you cannot use CSS selectors to select a preceding sibling of a different type or a parent element.

This example builds on the previous example to show how to select multiple elements with :has().

HTML

<section>
  <article>
    <h1>Morning Times</h1>
    <h2>Delivering you news every morning</h2>
    <p>
      Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod
      tempor incididunt ut labore et dolore magna aliqua.
    </p>
  </article>
  <article>
    <h1>Morning Times</h1>
    <h2>Delivering you news every morning</h2>
    <h3>8:00 am</h3>
    <p>
      Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod
      tempor incididunt ut labore et dolore magna aliqua.
    </p>
  </article>
</section>

CSS

section {
  display: flex;
  align-items: start;
  justify-content: space-around;
}

article {
  display: inline-block;
  width: 40%;
}

h1 {
  font-size: 1.2em;
}

h2 {
  font-size: 1em;
  color: rgb(150 149 149);
}

h3 {
  font-size: 0.9em;
  color: darkgrey;
}

h1,
h2,
h3 {
  margin: 0 0 1rem 0;
}

:is(h1, h2, h3):has(+ :is(h2, h3, h4)) {
  margin: 0 0 0.25rem 0;
}

Result

Here, the first :is() pseudo-class is used to select any of the heading elements in the list. The second :is() pseudo-class is used to pass a list of next-sibling selectors as an argument to :has(). The :has() pseudo-class helps to select any H1, H2, or H3 element that is immediately followed by (indicated by +) an H2, H3, or H4 element and the CSS rule reduces the spacing after such H1, H2, or H3 elements.

This selector could have also been written as:

:is(h1, h2, h3):has(+ h2, + h3, + h4) {
  margin: 0 0 0.25rem 0;
}

The :has() relational selector can be used to check if one of the multiple features is true or if all the features are true.

By using comma-separated values inside the :has() relational selector, you are checking to see if any of the parameters exist. x:has(a, b) will style x if descendant a OR b exists.

By chaining together multiple :has() relational selectors together, you are checking to see if all of the parameters exist. x:has(a):has(b) will style x if descendant a AND b exist.

body:has(video, audio) {
  /* styles to apply if the content contains audio OR video */
}
body:has(video):has(audio) {
  /* styles to apply if the content contains both audio AND video */
}

Interestingly, we can relate some CSS :has() constructs with the lookahead assertion in regular expressions because they both allow you to select elements (or strings in regular expressions) based on a condition without actually selecting the condition matching the element (or string) itself.

In the regular expression abc(?=xyz), the string abc is matched only if it is immediately followed by the string xyz. As it is a lookahead operation, the xyz is not included in the match.

The analogous construct in CSS would be .abc:has(+ .xyz): it selects the element .abc only if there is a next sibling .xyz. The part :has(+ .xyz) acts as a lookahead operation because the element .abc is selected and not the element .xyz.

Similarly, for the negative lookahead case, in the regular expression abc(?!xyz), the string abc is matched only if it is not followed by xyz. The analogous CSS construct .abc:has(+ :not(.xyz)) doesn't select the element .abc if the next element is .xyz.

• :is(), :where(), :not()
• CSS selectors and combinators
• CSS selector structure
• Selector list
• CSS selector module
• Locating DOM elements using selectors