CMS Design System

Dropdowns allow users to select one option from a temporary modal menu.

`<Dropdown>`

A Dropdown component can be used to render an HTML select menu. Any undocumented props that you pass to this component will be passed to the select element, so you can use this to set additional attributes if necessary.

Class-based component gives flexibility for active focus management by allowing refs to be passed.

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Props

React Properties Documentation
Name	Type	Description
`ariaLabel`	`string`	Adds `aria-label` attribute. When using `aria-label`, `label` should be empty string.
`className`	`string`	Additional classes to be added to the root element.
`children`	`React.ReactNode`	Used to define custom dropdown options (i.e. option groups). When using the `children` prop, `options` should be an empty list.
`defaultValue`	`number \| string`	Sets the initial selected state. Use this for an uncontrolled component; otherwise, use the `value` property.
`disabled`	`boolean`	Disables the entire field.
`errorMessage`	`React.ReactNode`
`errorMessageClassName`	`string`	Additional classes to be added to the error message
`errorPlacement`	`'top' \| 'bottom'`	Location of the error message relative to the field input
`fieldClassName`	`string`	Additional classes to be added to the select element
`focusTrigger`	`boolean`	Used to focus `select` on `componentDidMount()`
`hint`	`React.ReactNode`	Additional hint text to display
`id`	`string`	A unique ID to be used for the dropdown field. If one isn't provided, a unique ID will be generated.
`inputRef`	`(...args: any[]) => any`	Access a reference to the `select` element
`inversed`	`boolean`	Applies the "inverse" UI theme
`label`required	`React.ReactNode`	Label for the field. If using `Dropdown` without a label, provide an empty string for `label` and use the `ariaLabel` prop instead.
`labelClassName`	`string`	Additional classes to be added to the `FormLabel`.
`name`required	`string`	The field's `name` attribute
`options`required	`DropdownOptions[]`	The list of options to be rendered. Provide an empty list if using custom options via the `children` prop.
`onBlur`	`(...args: any[]) => any`
`onChange`	`(...args: any[]) => any`
`requirementLabel`	`React.ReactNode`	Text showing the requirement ("Required", "Optional", etc.). See Required and Optional Fields.
`size`	`'small' \| 'medium'`	If the component renders a select, set the max-width of the input either to `'small'` or `'medium'`.
`value`	`number \| string`	Sets the field's `value`. Use this in combination with `onChange` for a controlled component; otherwise, set `defaultValue`.

Guidance

When to use

Use sparingly. Use the dropdown component only when a user needs to choose from about seven to 15 possible options and you have limited space to display the options.

When to consider alternatives

Fewer than seven options. Use radio buttons or checkboxes instead.
More than 15 options. If the list of options is very long. Let users type the same information into a text input that suggests possible options instead.
Multi-select. If you need to allow users to select more than one option at once. Users often don’t understand how to select multiple items from dropdowns. Use checkboxes instead.
Site navigation. Use the navigation components instead.

Usage

Make sure to test. Test dropdowns thoroughly with members of your target audience. Several usability experts suggest they should be the “UI of last resort.” Many users find them confusing and difficult to use.
Avoid dependent options. Avoid making options in one dropdown menu change based on the input to another. Users often don’t understand how selecting an item in one impacts another.
Use a good default. When most users will (or should) pick a particular option, make it the selected default. If a good default is not an option, use a descriptive placeholder like - Select a state - as the selected default.
Avoid auto-submission. Don’t use JavaScript to automatically submit the form (or do anything else) when an option is selected. Auto-submission disrupts screen readers because they select each option as they read them.

View the "Forms" guidelines for additional guidance and best practices.

Accessibility

Customize accessibly. If you customize the dropdown, ensure it continues to meet the the accessibility requirements that apply to all form controls.
Always use a label. Make sure your dropdown has a label. Don’t replace it with the default menu option (for example, removing the “State” label and just having the dropdown read “Select a state” by default).
Avoid auto-submission. Don’t use JavaScript to automatically submit the form (or do anything else) when an option is selected. Auto-submission disrupts screen readers because they select each option as they read them.

Customization

The following Sass variables can be overridden to customize Dropdown components:

Variable	Default Core Theme Value
`$dropdown__background-color`	`$color-white`
`$dropdown__icon-size`	`10px`

Text Input Options

Variable	Default Core Theme Value
`$text-input__line-height`	`1.3`
`$text-input__background-color--disabled`	`$color-border`
`$text-input__border-width`	`2px`
`$text-input__border-color`	`$color-base`
`$text-input__border-color--disabled`	`$color-gray-light`
`$text-input__border-color--error`	`$color-error`
`$text-input__border-color--error--inverse`	`$color-error-light`
`$text-input__border-color--inverse`	`$color-black`
`$text-input__border-color--success`	`$color-green-light`
`$text-input__color`	`$color-base`
`$text-input__padding`	`8px`
`$text-input__border-radius`	`3px`

Learn more

[Form Guidelines]/guidelines/forms/)
Asking for a date of birth
Four steps for choosing form elements on the Web (PDF)
Dropdowns: Design Guidelines

<Dropdown>