Tabs

Associate tabs and panels with native keyboard behavior. Custom element

Tabs

Copy this markup

<ui-tabs id="package-tabs" value="install">
  <div role="tablist" aria-label="Package details" aria-orientation="horizontal">
    <button id="package-tabs-install-tab" value="install" role="tab" aria-controls="package-tabs-install-panel" aria-selected="true" tabindex="0" type="button">Install</button>
    <button id="package-tabs-usage-tab" value="usage" role="tab" aria-controls="package-tabs-usage-panel" aria-selected="false" tabindex="-1" type="button">Usage</button>
  </div>
  <section id="package-tabs-install-panel" role="tabpanel" aria-labelledby="package-tabs-install-tab" tabindex="0">
    <p>Install from the workspace package.</p>
  </section>
  <section id="package-tabs-usage-panel" role="tabpanel" aria-labelledby="package-tabs-usage-tab" tabindex="0" hidden>
    <p>Author native Light DOM anatomy.</p>
  </section>
</ui-tabs>

Install

Styles and registration

import '@timelessui/components/css/tokens.css'
import '@timelessui/components/css/tabs.css'
import '@timelessui/components/define/ui-tabs'

Anatomy

Parts are authored in your own markup and identified by the selector below, so your CSS can target the same anatomy without loading Timeless styles. Required parts must be present for the component to work. Private data-ui-internal-* hooks are written by the runtime and must never be authored.

Part	Required	Selector	Purpose
tablist	Yes	[role='tablist']	Container for the tabs.
tab	Yes	[role='tab']	One tab. Use <button type="button"> and give it a value; Timeless wires id, aria-controls, aria-selected, and tabindex.
tabpanel	Yes	[role='tabpanel']	One panel per tab, in the same order. Timeless wires id, aria-labelledby, and hidden.

Attributes

Every value below is implemented by the stylesheets this component ships. Boolean attributes are presence-based: author the attribute with no value, or omit it.

Attribute	Values	Default	Description
activation	automatic · manual	automatic	Whether moving focus with the arrow keys selects the tab immediately (automatic) or waits for Enter or Space (manual). Use manual when selecting a tab is expensive.
orientation	horizontal · vertical	horizontal	Arrow-key axis. Mirrored onto aria-orientation on the tablist during enhancement.
value	any string	—	The tab selected on load and after a form reset. Match a tab’s value attribute. Assign the value property for live changes.

Element API

Attributes above are the authoring surface. These are the DOM properties and events the registered element adds once it upgrades.

<ui-tabs>

Property	Type	Notes
activation	'automatic' | 'manual'	Reflects the activation attribute, documented above.
orientation	'horizontal' | 'vertical'	Reflects the orientation attribute, documented above.
defaultValue	string	Reflects the value attribute, documented above.
value	string	Live value. Assigning it does not rewrite the authored default and does not dispatch transition events.

Event	Detail	Description
ui-before-change	CustomEvent<TabsChangeDetail>	Cancelable proposal dispatched before the selected tab changes. Call preventDefault() to reject the transition and keep the current value.
ui-change	CustomEvent<TabsChangeDetail>	Dispatched after the selected tab has changed. Bubbles and is composed.

State

Native attributes, ARIA, and platform pseudo-classes are authoritative. Style state through the selectors below rather than adding your own state classes.

State	Source	How to express it
selected	aria	aria-selected="true" on the active tab.

Styling

Root identity: ui-tabs. Required stylesheets: tokens.css, tabs.css.

This component adds no custom properties of its own. Restyle it through the design tokens or your own CSS.

Design tokens this component reads (12)

These are global Atmosphere tokens. Change them once at the theme level rather than per component.

--ui-accent · --ui-accent-soft · --ui-duration-fast · --ui-ease-standard · --ui-fg · --ui-fg-muted · --ui-focus · --ui-line · --ui-radius-md · --ui-space-2 · --ui-space-4 · --ui-space-5

Accessibility

Keep the native elements, roles, and relationships shown in the example. Timeless adds only the state and keyboard coordination the platform does not already provide, and it never supplies your accessible names — those depend on your content.

Follows the Tabs pattern from the ARIA Authoring Practices Guide.

Key	Action
Arrow keys	Move focus between tabs along the orientation axis.
Home / End	Move focus to the first or last tab.
Enter / Space	Select the focused tab. Only needed when activation is manual; with automatic the arrow keys select as they move.

The tablist is one tab stop: Tab moves into the selected tab, then out to the panel. Timeless manages roving tabindex, aria-selected, and panel hidden.

Verify in context

Automated checks cover axe WCAG 2.2 A and AA rules on every documented route. Keyboard, zoom, forced-colors, and screen-reader review still belong to your application.

Before JavaScript runs

The markup above is complete and usable on its own: native controls submit, labels associate, and authored ARIA is already correct. Registration adds state synchronisation, focus management, and keyboard coordination on top of it.

More examples

Open Tabs in StoryLite for variants, controls, and manual testing.