Dropdown
No accessibility annotations are needed for dropdowns, but keep these considerations in mind if you are modifying Carbon or creating a custom component.
What Carbon provides
Carbon bakes keyboard operation into its components, improving the experience of blind users and others who operate via the keyboard. Carbon incorporates many other accessibility considerations, some of which are described below.
Keyboard interactions
A dropdown component and its variants multiselect and combo box are reached by
Tab
, with navigation of the options by Up
and Down
arrow keys. However,
the keys for opening the component and selecting its options are different for
each variant.
Dropdown
The default dropdown opens with Enter
, Space
, or Down arrow
, with focus
moving to the currently selected option. Arrow keys change options, and any
option with focus is selected with Space
or Enter
, which also closes the
dropdown. Pressing Esc
or Tab
closes a dropdown without changing the
selected option.
Multiselect
The multiselect opens with the Enter
or Space
keys, which are also used to
toggle the selection of any option. Once items are selected, a tag appears in
the field, showing a numerical representation of the number of items selected
along with an ‘x’. Pressing Esc
closes the multiselect. Pressing Delete
while focus is in the collapsed field will clear all selected options.
Combo box
The combo box’s operation is quite different, since it is a combination of a
text input and a dropdown. Enter
or the Up
or Down
arrow keys will open
the list of options, as will typing any character or string of characters (which
will also filter the list to only show items that match the typed string).
Pressing Esc
will clear the input and collapse the list. Pressing Enter
will
select a highlighted option and collapse the list. (If nothing is highlighted in
the list, pressing Enter
will toggle the combo box open and closed.) Space
cannot be used for selecting, as pressing it will submit a space character into
the filter string.
Development considerations
Keep these considerations in mind if you are modifying Carbon or creating a custom component.
- The dropdown and multiselect variant use a
button
witharia-haspopup="listbox"
. - The combo box uses an input with
role="combo box"
,aria-autocomplete="list"
,aria-haspopup="listbox"
andautocomplete="off"
. - The combo box uses
aria-controls
for a div withrole="listbox"
. - All variants use
aria-expanded
to track the state of the listbox. - See the ARIA authoring practices for combo box for more considerations.