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HomeWeb developmentAn Introduction to the :has() Selector in CSS — SitePoint

An Introduction to the :has() Selector in CSS — SitePoint


On this excerpt from Unleashing the Energy of CSS, we take a deep dive into how you can choose parts with the CSS :has() selector.

Heralded as “the dad or mum selector”, the :has() pseudo-class has far better vary than simply styling a component’s ancestor. With its availability in Safari 15.4+ and Chromium 105+, and behind a flag in Firefox, it’s a good time so that you can change into acquainted with :has() and its use instances.

As a pseudo-class, the essential performance of :has() is to type the factor it’s hooked up to — in any other case referred to as the “goal” factor. That is much like different pseudo-classes like :hover or :lively, the place a:hover is meant to type the <a> factor in an lively state.

Nonetheless, :has() can be much like :is(), :the place(), and :not(), in that it accepts a a listing of relative selectors inside its parentheses. This enables :has() to create advanced standards to check towards, making it a really highly effective selector.

To get a really feel for the way :has() works, let’s have a look at an instance of how you can apply it. Within the following selector, we’re testing if an <article> factor has an <img> factor as a baby:

article:has(img) {}

A doable results of this selector is proven within the picture under. Three article parts are proven, two containing photos and each having a palegreen background and completely different padding from the one with out a picture.

Three articles are shown, two containing images and both having a palegreen background and different padding from the one without an image

The selector above will apply so long as an <img> factor exists wherever with the <article> factor — whether or not as a direct baby or as a descendant of different nested parts.

If we need to ensure the rule applies provided that the <img> is a direct (un-nested) baby of the <article> factor, we will additionally embody the kid combinator:

article:has(> img) {}

The results of this variation is proven within the picture under. The identical three playing cards are proven, however this time solely the one the place the picture is a direct baby of the <article> has the palegreen background and padding.

The same three cards are shown, but this time only the one with the image as direct child has the palegreen background and padding

In each selectors, the kinds we outline are utilized to the goal factor, which is the <article>. This is the reason of us usually name :has() the “dad or mum” selector: if sure parts exist in a sure means, their “dad or mum” receives the assigned kinds.

Be aware: the :has() pseudo-class itself doesn’t add any specificity weight to the selector. Like :is() and :not(), the specificity of :has() is the same as the best specificity selector within the selector record. For instance, :has(#id, p, .class) may have the specificity afforded to an id. For a refresher on specificity, assessment the part on specificity in CSS Grasp, third Version.

We will additionally choose a goal factor if it’s adopted by a selected sibling factor utilizing the adjoining sibling combinator (+). Within the following instance, we’re choosing an <h1> factor provided that it’s immediately adopted by an <h2>:

h1:has(+ h2) {}

Within the picture under, two <article> parts are proven. Within the first one, as a result of the <h1> is adopted by an <h2>, the <h1> has a palegreen background utilized to it.

Two articles are shown. The first, with an h1 followed by an h2, has a palegreen background applied to the h1

Utilizing the final sibling combinator (~), we will verify if a selected factor is a sibling wherever following the goal. Right here, we’re checking if there’s a <p> factor someplace as a sibling of the <ul>:

ul:has(~ p) {}

The picture under reveals two <article> parts, every containing an unordered record. The second article’s record is adopted by a paragraph, so it has a palegreen background utilized.

Two articles, each containing an unordered list. The second article’s list is followed by a paragraph, so it has a palegreen background applied

The selectors we’ve used up to now have styled the goal factor hooked up to :has(), such because the <ul> in ul:has(~ p). Simply as with common selectors, our :has() selectors will be prolonged to be much more advanced, corresponding to setting styling situations for parts indirectly hooked up to the :has() selector.

Within the following selector, the kinds apply to any <p> parts which can be siblings of an <h2> that itself has an <h3> as an adjoining sibling:

h2:has(+ h3) ~ p

Within the picture under, two <article> parts are proven. Within the second, the paragraphs are styled with a palegreen background and an elevated left margin, as a result of the paragraphs are siblings of an <h2> adopted by an <h3>.

Two articles are shown. The second, which contains an h2 followed by an h3, has the paragraphs that follow the h3 styled with a palegreen background and increased left margin

Be aware: we’ll be extra profitable utilizing :has() if now we have understanding of the accessible CSS selectors. MDN gives a concise overview of selectors, and I’ve written a two-part collection on selectors with further sensible examples.

Bear in mind, :has() can settle for a listing of selectors, which we will consider as OR situations. Let’s choose a paragraph if it contains <a> _or_ <sturdy> _or_ <em>:

p:has(a, sturdy, em) {}

Within the picture under, there are two paragraphs. As a result of the second paragraph accommodates a <sturdy> factor, it has a palegreen background.

Two pararaphs are shown. The second contains a strong element that causes a palegreen background to be applied to the paragraph

We will additionally chain :has() selectors to create AND situations. Within the following compound selector, we’re testing each that an <img> is the primary baby of the <article>, and that the <article> accommodates an <h1> adopted by an <h2>:

article:has(> img:first-child):has(h1 + h2) {}

The picture under reveals three <article> parts. The second article has a palegreen background (together with different styling) as a result of it accommodates each a picture as a primary baby and an <h1> adopted by an <h2>.

Three articles are shown, each containing an h1. The second article, which has an h1 + h2 and an image as a first child, has a palegreen background, and a serif style for the h1

You’ll be able to assessment all of those fundamental selector examples within the following CodePen demo.

See the Pen
:has() selector syntax examples
by SitePoint (@SitePoint)
on CodePen.

This text is excerpted from Unleashing the Energy of CSS: Superior Methods for Responsive Person Interfaces, accessible on SitePoint Premium.



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