The CSS :has() selector is way more than a “Parent Selector”

# CSS :has()?

As per selectors-4 specification:

The :has() CSS pseudo-class represents an element if any of the selectors passed as parameters match at least one element.

This selector is dubbed “the parent selector”, as the default cases indeed allow you to select a parent element that has certain children.

/* Matches <a> elements that contain an <img> child */
a:has(img) { … }

/* Matches <a> elements that directly contain an <img> child */
a:has(> img) { … }

/* Matches <section> elements that don’t contain any heading elements: */
section:not(:has(h1, h2, h3, h4, h5, h6))

Cool!

# More than a parent selector

The :has() selector is way more than that just a parent selector though. As Adrian Bece shared in his post on Smashing Magazine:

/*  Matches <figure> elements that have a <figcaption> as a child element */
figure:has(figcaption) { … }

/* Matches <img> elements that is a child of a <figure> that contains a <figcaption> child element */
figure:has(figcaption) img { … }

Here’s a pen:

In browsers that support :has() you should see a red dashed border around the top image.

Here’s another example, from the spec:

/* Matches <h1> elements only if they have a <p> element directly following them */
h1:has(+ p) { … }

Yes, that one also works because the :has() relational pseudo-class selector accepts a <forgiving-relative-selector-list> as an argument. That’s is a list of <relative-selector>s which can contain any of the combinators we already know: +, ~, >, …

# Other peculiar traits

Just like CSS :is(), CSS :has() has these specific traits:

1. The selector list of :has() is forgiving
2. The specificity of :has() is that of its most specific argument

Hit the post on CSS :is() for more info on this.

# Browser Support

As mentioned only Safari TP 137 supports it (unflagged) at the time of writing. The Chromium team is currently working on implementing it as well. No word on Firefox.

• WebKit/Safari: Issue #227702 — RESOLVED FIXED
• Blink/Chromium: Issue #669058 — Assigned (Open)
• Gecko/Firefox: Issue #418039 — NEW

The pen embedded below will indicate if the browser you are using supports CSS :has() or not:

Interative Support Chart (using data from CanIUse.com), for all browsers:

To help spread the contents of this post, feel free to retweet its announcement tweet:

The CSS `:has()` selector is way more than a “Parent Selector”.

🔗 https://t.co/rzAiRG8DQk

🏷 #css #selectors pic.twitter.com/cwpv7esjwb

— Bram.us (@bramusblog) December 21, 2021