CSS Has Pseudo

CSS Has Pseudo lets you style elements relative to other elements in CSS, following the Selectors Level 4 specification.

a:has(> img) {
  /* style links that contain an image */
}

h1:has(+ p) {
  /* style level 1 headings that are followed by a paragraph */
}

section:not(:has(h1, h2, h3, h4, h5, h6)) {
  /* style sections that don’t contain any heading elements */
}

body:has(:focus) {
  /* style the body if it contains a focused element */
}

Usage

From the command line, transform CSS files that use :has selectors:

npx css-has-pseudo SOURCE.css --output TRANSFORMED.css

Next, use your transformed CSS with this script:

<link rel="stylesheet" href="TRANSFORMED.css">
<script src="https://unpkg.com/css-has-pseudo/dist/browser-global.js"></script>
<script>cssHasPseudo(document)</script>

⚠️ Please use a versioned url, like this : https://unpkg.com/css-has-pseudo@3.0.0/dist/browser-global.js Without the version, you might unexpectedly get a new major version of the library with breaking changes.

⚠️ If you were using an older version via a CDN, please update the entire url. The old URL will no longer work in a future release.

That’s it. The script is 765 bytes and works in most browser versions, including Internet Explorer 11. With a Mutation Observer polyfill, the script will work down to Internet Explorer 9.

See README BROWSER for more information.

How it works

The PostCSS plugin clones rules containing :has, replacing them with an alternative [:has] selector.

body:has(:focus) {
  background-color: yellow;
}

section:not(:has(h1, h2, h3, h4, h5, h6)) {
  background-color: gray;
}

/* becomes */

body[\:has\(\:focus\)] {
  background-color: yellow;
}

body:has(:focus) {
  background-color: yellow;
}

section[\:not-has\(h1\,\%20h2\,\%20h3\,\%20h4\,\%20h5\,\%20h6\)] {
  background-color: gray;
}

section:not(:has(h1, h2, h3, h4, h5, h6)) {
  background-color: gray;
}

Next, the JavaScript library adds a [:has] attribute to elements otherwise matching :has natively.

<body :has(:focus)>
  <input value="This element is focused">
</body>

Current Tags

4.0.2 ... latest (3 years ago)

4 Versions

4.0.2 ... 3 years ago
3.0.4 ... 4 years ago
3.0.3 ... 4 years ago
0.10.0 ... 7 years ago