The below date picker demonstrates an implementation of the Combobox Pattern that opens a dialog.
The date picker dialog is opened by activating the choose date button or by moving keyboard focus to the combobox and pressing Down Arrow or Alt + Down Arrow.
The dialog contains an implementation of the grid pattern for displaying a calendar and enabling selection of a date.
Additional buttons in the dialog are available for changing the month and year shown in the grid.
Editable Combobox with Grid Popup: An editable combobox that presents suggestions in a grid, enabling users to navigate descriptive information about each suggestion.
Example
(date format: mm/dd/yyyy)
December 2020
Su
Mo
Tu
We
Th
Fr
Sa
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
Accessibility Features
The description of the date format is associated with the combobox via aria-describedby, making it available to assistive technologies as an accessible description.
While the down arrow icon is excluded from the Tab sequence as specified in the combobox design pattern, it is made accessible to assistive technologies as the Choose Date button.
This enables assistive technology users who might not have a keyboard, e.g., someone using a touch-based screen reader, to open the date picker dialog.
In the dialog, shortcut keys are assigned to the additional buttons for changing the month and year displayed in the calendar.
Keyboard help is displayed at the bottom of the dialog.
A live region is used to announce it to screen reader users when focus moves into the grid.
The calendar heading displaying the month and year is marked up as a live region so screen reader users get feedback from the buttons and keyboard commands that change the month and year.
To facilitate compact visual design in the calendar, the day names in the column headers are abbreviated to two characters.
However, this makes it more difficult for screen reader users to understand the day names.
So, full day names are provided to assistive technologies in the HTML abbr attribute on the column headers, enabling screen readers to announce the full names when users navigate the grid.
Focus and hover styling of the controls support operating system high contrast settings via the CSS border property:
When a button or date cell receives focus a border is added.
When hovering over a button or date cell with a pointing device a border is added.
By default, buttons and date cells do not have a border; padding provides a placeholder space for focus and hover styling.
Keyboard Support
Combobox
Key
Function
Down Arrow, ALT + Down Arrow
Open the date picker dialog.
If the combobox contains a valid date, moves focus to that date in the calendar grid.
Otherwise, moves focus to current date, i.e., today's date.
Date Picker Dialog
Key
Function
ESC
Closes the dialog and moves focus to the combobox.
TAB
Moves focus to next element in the dialog Tab sequence.
Note that, as specified in the Grid Pattern, only one element in the calendar grid is in the Tab sequence.
If focus is on the last button (i.e., "OK"), moves focus to the first button (i.e. "Previous Year").
Shift + TAB
Moves focus to previous element in the dialog Tab sequence.
Note that, as specified in the Grid Pattern, only one element in the calendar grid is in the Tab sequence.
If focus is on the first button (i.e., "Previous Year"), moves focus to the last button (i.e. "OK").
Date Picker Dialog: Calendar Buttons
Key
Function
Space, Enter
Change the month and/or year displayed in the calendar grid.
Date Picker Dialog: Date Grid
Key
Function
Space
Selects the date.
Updates the value of the combobox with the selected date.
Enter
Selects the date.
Updates the value of the combobox with the selected date.
Closes the dialog and moves focus to the combobox.
Up Arrow
Moves focus to the same day of the previous week.
Down Arrow
Moves focus to the same day of the next week.
Right Arrow
Moves focus to the next day.
Left Arrow
Moves focus to the previous day.
Home
Moves focus to the first day (e.g. Sunday) of the current week.
End
Moves focus to the last day (e.g. Saturday) of the current week.
PageUp
Changes the grid of dates to the previous month.
Moves focus to the day of the month that has the same number.
If that day does not exist, moves focus to the last day of the month.
Shift+ PageUp
Changes the grid of dates to the same month in the previous year.
Moves focus to the day of the month that has the same number.
If that day does not exist, moves focus to the last day of the month.
PageDown
Changes the grid of dates to the next month.
Moves focus to the day of the month that has the same number.
If that day does not exist, moves focus to the last day of the month.
Shift+ PageDown
Changes the grid of dates to the same month in the next year.
Moves focus to the day of the month that has the same number.
If that day does not exist, moves focus to the last day of the month.
Date Picker Dialog: OK and Cancel Buttons
Key
Function
Space, Enter
Activates the button:
"Cancel": Closes the dialog, moves focus to combobox, does not update combobox value.
"OK": Closes the dialog, moves focus to combobox, updates date in combobox.
Role, Property, State, and Tabindex Attributes
Combobox
Role
Attribute
Element
Usage
combobox
input
Identifies the input element as a combobox.
aria-haspopup="dialog"
input
Indicates that the combobox opens a dialog.
aria-expanded="false"
input
Indicates that the combobox is collapsed, i.e., the "Choose Date" dialog is not displayed.
aria-expanded="true"
input
Indicates that the combobox is expanded, i.e., the "Choose Date" dialog is open.
aria-autocomplete="none"
input
Indicates the combobox does not support autocomplete.
aria-controls="IDREF"
input
Identifies the element controlled by the combobox.
aria-describedby="IDREF"
input
Identifies the element that provides an accessible description for the combobox, enabling assistive technologies to associate the date format description with the input.
Choose Date Button
Role
Attribute
Element
Usage
tabindex="-1"
button
Excludes the button (i.e., the down arrow icon) from the Tab sequence as specified by the combobox design pattern.
aria-label="string"
button
Defines the accessible name as "Choose Date", which matches the title of the dialog opened by activating the button.
Date Picker Dialog
Role
Attribute
Element
Usage
dialog
div
Identifies the element as a dialog.
aria-modal="true"
div
Indicates the dialog is modal.
aria-label="Choose Date"
div
Defines the accessible name for the dialog.
aria-live="polite"
h2
Indicates that screen readers should automatically announce the element containing the currently displayed month and year when they change.
The polite value indicates that other announcements should not be interrupted.
aria-live="polite"
div
Indicates the element that displays information about keyboard commands for navigating the grid should be automatically announced by screen readers.
The script slightly delays display of the information, so screen readers are more likely to announce it after announcing focus change events.
The polite value indicates that other announcements should not be interrupted.
Date Picker Dialog: Calendar Navigation Buttons
Role
Attribute
Element
Usage
aria-label="String"
button
Defines the accessible name of the button (e.g. "Next Year").
Date Picker Dialog: Date Grid
Role
Attribute
Element
Usage
grid
table
Identifies the table element as a grid widget.
Since the grid role is applied to a table element, the row, columnheader, and gridcell roles do not need to be specified because they are implied by tr, th, and td tags.
aria-labelledby="IDREF"
table
Identifies the element that provides the accessible name for the grid, which is the h2 that shows the month and year of the dates displayed in the grid.
tabindex="0"
td
Makes the gridcell focusable and includes it in the dialog Tab sequence.
Set dynamically by the JavaScript when the element is to be included in the dialog Tab sequence.
At any given time, only one gridcell within the grid is in the dialog Tab sequence.
Set on the gridcell representing the current value of the combobox; no other gridcells have aria-selected specified.
Note: Since the names of the days of the week in the column headers are abbreviated to two characters, they may be difficult to understand when announced by a screen reader.
An alternative column header name can be provided to screen readers by applying the abbr attribute to the th elements.
So, each th element includes an abbr attribute containing the full spelling of the name of the day for that column.
