Number Field `<mv-number-field>`

Numeric input with − / + buttons (press and hold to accelerate), bounds and step, arrow keys and mouse wheel, Intl formatting (currency, percent, unit) and a “scrub” label: drag horizontally to change the value, with optional pointer lock.

Category	Forms
Type	Web Component (`<mv-number-field>`)
Status	stable
Keywords	number, stepper, spinbutton, currency, percent, scrub, intl, form-associated

When to use

A bounded number like a count, percentage or price must be typed or nudged with - and + buttons
The value should be displayed formatted as currency, percent or a unit while submitting the raw number
Power users benefit from dragging the label to scrub the value quickly

Avoid when

It is a product quantity on a cart line or product page with stock limits → use Quantity instead
A compact design-tool inspector needs scrubbing, expressions and units → use Scrub Field instead
The exact value matters less than a rough position within a range → use Slider instead

Install

node scripts/add.mjs number-field --out ./src/marvelous

AI agent with the Marvelous UI MCP server: install_components({ slugs: ["number-field"], target_dir: "<absolute path>/src/marvelous", framework: "react" }).

Files copied (dependencies included): tokens/tokens.css, core/base.css, core/dom.js, core/element.js, core/i18n.js, core/motion.js, components/number-field/number-field.js, components/number-field/number-field.css.

Usage

Canonical markup, to start from and customize with attributes, data-* and CSS variables:

<form id="number-field-demo-form" style="display:grid;grid-template-columns:repeat(2,minmax(0,10.5rem));gap:1.25rem 1.5rem;justify-content:center">
  <mv-number-field label="Quantity" name="quantity" value="2" min="1" max="20" style="--mv-number-field-width:100%"></mv-number-field>
  <mv-number-field label="Unit price" name="price" value="24.9" min="0" step="0.5" format="currency" currency="USD" wheel style="--mv-number-field-width:100%"></mv-number-field>
  <mv-number-field label="Discount" name="discount" value="0.15" min="0" max="0.5" step="0.05" format="percent" layout="stacked" style="--mv-number-field-width:100%"></mv-number-field>
  <mv-number-field id="number-field-demo-weight" label="Weight" name="weight" value="2.4" min="0" max="30" step="0.1" format="unit" unit="kilogram" scrub pointer-lock style="--mv-number-field-width:100%"></mv-number-field>
  <p style="grid-column:1/-1;margin:0;text-align:center;font-size:.75rem;color:var(--mv-fg-muted)">Hold − / + to repeat · ↑/↓ on the keyboard (Shift ×10) · drag the “Weight” label horizontally.</p>
</form>

API

Attributes

Name	Type	Default	Description
`label`	string		Built-in label (also acts as the “scrub” area).
`name`	string		Form field name (raw numeric value, e.g. “0.15”).
`value`	number		Initial value (also used on reset).
`min / max`	number		Bounds; the value is clamped and buttons disable at the limits.
`step`	number	`1`	Step (also sets the precision).
`large-step`	number	`step × 10`	Step with Shift, Page↑/Page↓.
`format`	decimal \| currency \| percent \| unit	`decimal`	Intl.NumberFormat style (percent: 0.15 displays as “15%”).
`currency`	string	`USD`	ISO 4217 code for format=currency.
`unit`	string		Intl unit for format=unit (kilogram, centimeter, liter…).
`decimals`	number		Fixed number of displayed decimals.
`locale`	string	`en-US`	Formatting and input locale (both “,” and “.” are accepted). The value auto follows the page language (nearest lang); without the attribute, en-US unless the app registered the page language with setStrings() (core/i18n.js).
`layout`	split \| stacked	`split`	− / + on either side, or chevrons stacked on the right.
`wheel`	boolean		The mouse wheel changes the value while the field has focus.
`scrub`	boolean		Dragging horizontally on the label changes the value (Shift ×10, Alt ×0.1).
`pointer-lock`	boolean		Locks the pointer while scrubbing (infinite drag + virtual cursor).
`scrub-pixels`	number	`4`	Pixels of movement per step.
`placeholder`	string		Text shown when empty.
`required / disabled / readonly / invalid`	boolean		Form states.
`data-size`	sm \| lg		Height.

Properties

Name	Type	Description
`value`	number \| null	Numeric value.
`valueAsNumber`	number	Value or NaN.
`strings`	Partial<Record<string, string>>	Overrides for the default text (en-US): decrease and increase (stepper button labels), valueMissing (required message). App-wide translations: setStrings() from core/i18n.js, under the key "number-field". Can be set before the element is defined.

Methods

Name	Description
`stepUp(n) / stepDown(n)`	Adds / removes n steps.
`focus()`	Focuses the input.
`checkValidity() / reportValidity()`	Native validation.

Events

Name	Description
`mv-change`	detail: { value, formatted } on every committed change (step, typing, scrub).

Content structure

Name	Description
`[data-scrub]`	Extra child element used as a scrub area.

CSS classes

Name	Description
`mv-number-field-label / -group / -input / -btn / -cursor`	Generated parts; data-scrubbing while dragging.

CSS variables

Name	Default	Description
`--mv-number-field-width`	`9.5rem`	Width.
`--mv-number-field-radius`	`var(--mv-radius-md)`	Group radius.

Accessibility

APG Spinbutton pattern: the input has role=spinbutton, aria-valuenow, aria-valuetext (formatted value, e.g. “$24.90”), aria-valuemin/max, and the name of the built-in or associated <label>. ↑/↓ (Shift ×10), Page↑/↓, Home/End (bounds), Enter commits, Escape cancels typing. The −/+ buttons are out of the tab order (tabindex=-1) and labeled “Decrease” / “Increase”. Scrubbing is a pointer shortcut, never the only way to change the value.