Editable Combobox With List Autocomplete Example

The below combobox for choosing the name of a US state or territory demonstrates the ARIA design pattern for combobox. The design pattern describes four types of autocomplete behavior. This example illustrates the autocomplete behavior known as list autocomplete with manual selection. If the user types one or more characters in the edit box and the typed characters match the beginning of the name of one or more states or territories, a listbox popup appears containing the matching names. When the listbox appears, a suggested name is not automatically selected. Thus, after typing, if the user tabs or clicks out of the combobox without choosing a value from the listbox, the typed string becomes the value of the combobox. Note that this implementation enables users to input the name of a state or territory, but it does not prevent input of any other arbitrary value.

Similar examples include:

Select-Only Combobox: A single-select combobox with no text input that is functionally similar to an HTML select element.
Editable Combobox with Both List and Inline Autocomplete: An editable combobox that demonstrates the autocomplete behavior known as list with inline autocomplete.
Editable Combobox Without Autocomplete: An editable combobox that demonstrates the behavior associated with aria-autocomplete=none.
Editable Combobox with Grid Popup: An editable combobox that presents suggestions in a grid, enabling users to navigate descriptive information about each suggestion.
Date Picker Combobox: An editable date input combobox that opens a dialog containing a calendar grid and buttons for navigating by month and year.

Example

State

Keyboard Support

The example combobox on this page implements the following keyboard interface. Other variations and options for the keyboard interface are described in the Keyboard Interaction section of the combobox design pattern.

Textbox

Key	Function
`Down Arrow`	If the textbox is not empty and the listbox is displayed, moves visual focus to the first suggested value. If the textbox is empty and the listbox is not displayed, opens the listbox and moves visual focus to the first option. In both cases DOM focus remains on the textbox.
`Alt + Down Arrow`	Opens the listbox without moving focus or changing selection.
`Up Arrow`	If the textbox is not empty and the listbox is displayed, moves visual focus to the last suggested value. If the textbox is empty, first opens the listbox if it is not already displayed and then moves visual focus to the last option. In both cases DOM focus remains on the textbox.
`Enter`	Closes the listbox.
`Escape`	If the listbox is displayed, closes it. If the listbox is not displayed, clears the textbox.
Standard single line text editing keys	Keys used for cursor movement and text manipulation, such as `Delete` and `Shift + Right Arrow`. An HTML `input` with `type="text"` is used for the textbox so the browser will provide platform-specific editing keys.

Listbox Popup

NOTE: When visual focus is in the listbox, DOM focus remains on the textbox and the value of aria-activedescendant on the textbox is set to a value that refers to the listbox option that is visually indicated as focused. Where the following descriptions of keyboard commands mention focus, they are referring to the visual focus indicator. For more information about this focus management technique, see Using aria-activedescendant to Manage Focus.

Key	Function
`Enter`	Sets the textbox value to the content of the focused option in the listbox. Closes the listbox. Sets visual focus on the textbox.
`Escape`	Closes the listbox. Sets visual focus on the textbox.
`Down Arrow`	Moves visual focus to the next option. If visual focus is on the last option, moves visual focus to the first option. Note: This wrapping behavior is useful when `Home` and `End` move the editing cursor as described below.
`Up Arrow`	Moves visual focus to the previous option. If visual focus is on the first option, moves visual focus to the last option. Note: This wrapping behavior is useful when `Home` and `End` move the editing cursor as described below.
`Right Arrow`	Moves visual focus to the textbox and moves the editing cursor one character to the right.
`Left Arrow`	Moves visual focus to the textbox and moves the editing cursor one character to the left.
`Home`	Moves visual focus to the textbox and places the editing cursor at the beginning of the field.
`End`	Moves visual focus to the textbox and places the editing cursor at the end of the field.
Printable Characters	Moves visual focus to the textbox. Types the character in the textbox. Options in the listbox are filtered based on characters in the textbox.

Button

The button has been removed from the tab sequence of the page, but is still important to assistive technologies for mobile devices that use touch events to open the list of options.

Role, Property, State, and Tabindex Attributes

The example combobox on this page implements the following ARIA roles, states, and properties. Information about other ways of applying ARIA roles, states, and properties is available in the Roles, States, and Properties section of the combobox design pattern.

Textbox

Role	Attribute	Element	Usage
`combobox`		`input[type="text"]`	Identifies the input as a combobox.
	`aria-autocomplete="list"`	`input[type="text"]`	Indicates that the autocomplete behavior of the text input is to suggest a list of possible values in a popup and that the suggestions are related to the string that is present in the textbox.
	`aria-controls="#IDREF"`	`input[type="text"]`	Identifies the element that serves as the popup.
	`aria-expanded="false"`	`input[type="text"]`	Indicates that the popup element is not displayed.
	`aria-expanded="true"`	`input[type="text"]`	Indicates that the popup element is displayed.
	`id="string"`	`input[type="text"]`	Referenced by `for` attribute of `label` element to provide an accessible name. Recommended naming method for HTML input elements because clicking label focuses input.
	`aria-activedescendant="IDREF"`	`input[type="text"]`	When an option in the listbox is visually indicated as having keyboard focus, refers to that option. When navigation keys, such as `Down Arrow`, are pressed, the JavaScript changes the value. Enables assistive technologies to know which element the application regards as focused while DOM focus remains on the `input` element. For more information about this focus management technique, see Using aria-activedescendant to Manage Focus.

Listbox Popup

Role	Attribute	Element	Usage
`listbox`		`ul`	Identifies the `ul` element as a `listbox`.
	`aria-label="States"`	`ul`	Provides a label for the `listbox`.
`option`		`li`	Identifies the element as a `listbox` `option`. The text content of the element provides the accessible name of the `option`.
	`aria-selected="true"`	`li`	Specified on an option in the listbox when it is visually highlighted as selected. Occurs only when an option in the list is referenced by `aria-activedescendant`.

Button

Attribute	Element	Usage
`tabindex="-1"`	`button`	Removes the button from the tab sequence of the page because its function is redundant with the keyboard operation of the combobox.
`aria-label="States"`	`button`	Provides a label for the `button`.
`aria-controls="#IDREF"`	`button`	Identifies the element that serves as the popup.
`aria-expanded="false"`	`button`	Indicates that the popup element is not displayed.
`aria-expanded="true"`	`button`	Indicates that the popup element is displayed.

Javascript and CSS Source Code

CSS: combobox-autocomplete.css
Javascript: combobox-autocomplete.js

Editable Combobox With List Autocomplete Example

Example

Keyboard Support

Textbox

Listbox Popup

Button

Role, Property, State, and Tabindex Attributes

Textbox

Listbox Popup

Button

Javascript and CSS Source Code

HTML Source Code