Lily Design System™

Float Button

A float button is a floating action button anchored to a viewport corner. It uses inline position: fixed as the documented headless behavior and a required aria-label so screen readers announce its purpose.

Use it for primary single-action shortcuts (compose, scroll-to-top, new chat, contact support) that should remain reachable regardless of scroll position.

Example

FloatButton
Show demo markup 
<div class="float-button" aria-label="a floating action button anchored to a viewport corner">FloatButton</div>
Usage example 
<script lang="ts">
  import FloatButton from './FloatButton.svelte';
</script>

<FloatButton label="Open help" onclick={openHelp}>
  <span aria-hidden="true">?</span>
</FloatButton>
Show Svelte source 
// In your Svelte component:
import FloatButton from "lily-design-system-svelte-headless/components/FloatButton/FloatButton.svelte";

<FloatButton>FloatButton</FloatButton>

Usage

<FloatButton label="Compose" position="bottom-right" onclick={openComposer}>
  <svg>...</svg>
</FloatButton>
<FloatButton label="Scroll to top" position="bottom-left" onclick={scrollTop}>
  ↑
</FloatButton>

Props

  • label: string (required) -- aria-label
  • position: "top-left" | "top-right" | "bottom-left" | "bottom-right" (default: "bottom-right")
  • disabled: boolean (default: false)
  • type: "button" | "submit" | "reset" (default: "button")
  • onclick / onClick: callback (optional)
  • children: slot -- icon content
  • ...restProps: any additional HTML attributes

Keyboard Interactions

  • Tab: Focus the button
  • Enter: Activate the button
  • Space: Activate the button
  • (All handled natively by <button> element)

ARIA

  • Implicit button role from <button> element
  • aria-label is the entire accessible name (required)
  • aria-disabled from native disabled attribute
  • data-position exposes the corner anchor for CSS hooks

When to Use

  • Use for one or two persistent shortcuts that should always be reachable.
  • Use for compose, contact, scroll-to-top, or other ever-available actions.

When Not to Use

  • Do not use for primary navigation — use a navigation menu or tab bar.
  • Do not stack many float buttons — clutter and overlap reduce usability.
  • Do not omit label — icon-only buttons without an accessible name fail WCAG.

Headless

Renders a <button> with inline position: fixed style and the right corner offset. The icon glyph, size, focus indicator, hover state, and elevation/shadow are entirely the consumer's responsibility.

Styles

Consumer CSS targets the float-button class. Use data-position to pick the corner. Provide a minimum 44×44 px touch target, a clear focus indicator, and elevation that matches the surrounding theme.

Testing

  • Verify the component renders a <button> with class float-button
  • Verify aria-label is present and equals the label prop
  • Verify type defaults to "button"
  • Verify position defaults to "bottom-right" and emits data-position
  • Verify inline style includes position: fixed
  • Verify inline style includes the correct corner offset for each position
  • Verify disabled attribute is applied when disabled is true
  • Verify the click handler fires on Enter, Space, and click

Advice

  • Designers: Place the float button where it will not obscure key content. Maintain sufficient contrast against any underlying scroll surface.
  • Developers: Always supply label. Avoid stacking multiple float buttons that overlap; group related actions inside a single trigger.

Implementation Notes

  • Renders a native <button> element with class float-button
  • Inline style applies position: fixed plus the corner offset for the chosen position
  • position defaults to "bottom-right" and emits data-position
  • Default offset is 1rem from each edge
  • label is required and sets aria-label
  • Defaults to type="button" to prevent accidental form submissions
  • Native disabled attribute prevents click events automatically
  • Children render the icon content (decorative)

Related components

  • button — a generic clickable button element
  • icon-button — a button containing only an icon with a required accessible label
  • affix — a wrapper that pins its content to a viewport position while the page scrolls

References

  • WAI-ARIA Button Pattern: https://www.w3.org/WAI/ARIA/apg/patterns/button/
  • WCAG 4.1.2 Name, Role, Value: https://www.w3.org/WAI/WCAG22/Understanding/name-role-value
  • Ant Design FloatButton: https://ant.design/components/float-button

Canonical contract

Generated from this component's canonical metadata — the machine-checked source the implementations are held to.

Metadata

  • Component: float-button
  • PascalCase: FloatButton
  • Description: a floating action button anchored to a viewport corner
  • Status: beta — implemented and unit-tested in all seven frameworks with an axe-clean demo page; not yet exercised in composed flows
  • HTML tag: <button>
  • CSS class: .float-button
  • Interactive: yes

ARIA

  • Implicit button role from <button>
  • aria-label is the entire accessible name (required)
  • aria-disabled from native disabled attribute
  • data-position attribute exposes corner anchor

Keyboard

  • Tab: Focus the button
  • Enter: Activate the button
  • Space: Activate the button

Props

  • label: string (REQUIRED)
  • position: "top-left" | "top-right" | "bottom-left" | "bottom-right" (default: "bottom-right")
  • disabled: boolean (default: false)
  • type: "button" | "submit" | "reset" (default: "button")
  • onclick / onClick: callback (optional)
  • children: slot — icon content
  • ...restProps: any additional HTML attributes