The ::part
CSS pseudo-element represents any element within a shadow tree that has a matching part
attribute.
custom-element::part(foo) { /* Styles to apply to the `foo` part */ }
::part( <ident>+ )
<template id="tabbed-custom-element"> <style type="text/css"> *, ::before, ::after { box-sizing: border-box; padding: 1rem; } :host { display: flex; } </style> <div part="tab active">Tab 1</div> <div part="tab">Tab 2</div> <div part="tab">Tab 3</div> </template> <tabbed-custom-element></tabbed-custom-element>
tabbed-custom-element::part(tab) { color: #0c0dcc; border-bottom: transparent solid 2px; } tabbed-custom-element::part(tab):hover { background-color: #0c0d19; border-color: #0c0d33; } tabbed-custom-element::part(tab):hover:active { background-color: #0c0d33; } tabbed-custom-element::part(tab):focus { box-shadow: 0 0 0 1px #0a84ff inset, 0 0 0 1px #0a84ff, 0 0 0 4px rgba(10, 132, 255, 0.3); } tabbed-custom-element::part(active) { color: #0060df; border-color: #0a84ff !important; }
let template = document.querySelector("#tabbed-custom-element"); globalThis.customElements.define(template.id, class extends HTMLElement { constructor() { super(); this.attachShadow({ mode: "open" }); this.shadowRoot.appendChild(template.content); } });
Specification | Status | Comment |
---|---|---|
Shadow Parts The definition of '::part' in that specification. | Working Draft | Initial definition. |
Desktop | ||||||
---|---|---|---|---|---|---|
::part |
73 | 79 | 72
|
No | 60 | 13.1 |
Mobile | ||||||
---|---|---|---|---|---|---|
::part |
73 | 73 | No | 52 | 13.4 | 11.0 |
part
attribute - Used to define parts which can be selected by the ::part()
selectorexportparts
attribute - Used to transitively export shadow parts from a nested shadow tree into a containing light tree.
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https://developer.mozilla.org/en-US/docs/Web/CSS/::part