Actions Menu Button Example Using aria-activedescendant

This example demonstrates how the menu button 설계 패턴 can be used to create a button that opens an actions menu. In this example, choosing an action from the menu will cause the chosen action to be displayed in the Last Action edit box.

This implementation uses aria-activedescendant to manage focus in the menu.

유사한 예는 다음과 같습니다:

Example

접근성 특성

  1. A down arrow icon is included to help users understand that the button opens a menu.
  2. To support operating system high contrast settings:
    • Because transparent borders are visible on some systems with operating system high contrast settings enabled, transparency cannot be used to create a visual difference between the element that is focused an other elements. Instead of using transparency, the focused element has a thicker border and less padding. When an element receives focus, its border changes from 1 to 3 pixels and padding is reduced by 2 pixels. When an element loses focus, its border changes from 3 pixels to 1 and padding is increased by 2 pixels.
    • Because background color and text color styles can be overridden by operating system high contrast settings, a border is used to ensure the button has a visible boundary when high contrast mode is enabled.
    • To ensure the arrow icons used to indicate the expanded or collapsed state have sufficient contrast with the background when high contrast settings invert colors, the CSS currentcolor value for the fill and stroke properties of the SVG polygon element is used to synchronize the color with text content. If specific colors are used to specify the fill and stroke properties, these colors will remain the same in high contrast mode, which could lead to insufficient contrast between the icon and the background or even make the icon invisible if its color matches the high contrast mode background.

키보드 지원

Menu Button

키 기능
Down Arrow
Space
Enter		 Opens menu and moves focus to first menuitem
Up Arrow Opens menu and moves focus to last menuitem

Menu

Key 기능
Enter
  • Activates the menu item, causing the Last Action textbox to be updated.
  • Closes the menu.
  • Sets focus on the menu button
Escape
  • Closes the menu.
  • Sets focus to the menu button.
Up Arrow
  • Moves focus to the previous menu item.
  • If focus is on the first menu item, moves focus to the last menu item.
Down Arrow
  • Moves focus to the next menu item.
  • If focus is on the last menu item, moves focus to the first menu item.
Home Moves focus to the first menu item.
End Moves focus to the last menu item.
A-Z
a-z
  • Moves focus to the next menu item with a label that starts with the typed character if such an menu item exists.
  • Otherwise, focus does not move.

Role, Property, State, Tabindex 어트리뷰트

Menu Button

역할(role) 어트리뷰트 엘리먼트 사용법
aria-haspopup="true" button
  • Indicates the button element opens a menu.
  • NOTE: While ARIA does not include a role specifically for menu buttons, most platform accessibility APIs include a menubutton role. Consequently, on such platforms, assistive technologies, such as screen readers, identify buttons that have aria-haspopup set to either true or menu as menu buttons.
aria-controls="IDREF" button
  • Refers to the menu element controlled by the menu button.
  • Optional attribute: assistive technology users can operate the menu if not present.
aria-expanded="true" button
  • Added when the menu is open.
  • Indicates that the menu is displayed and that activating the menu button closes the menu.
  • The aria-expanded attribute is removed when the menu is closed.
  • Included to support touch devices where screen reader users can touch the menu button when the menu is displayed. Keyboard users cannot focus the menu button when the menu is open.

Menu

역할(role) 어트리뷰트 엘리먼트 사용법
menu ul Identifies the ul element as a menu.
aria-labelledby="IDREF" ul
  • Refers to the element that contains the accessible name for the menu.
  • The menu is labeled by the menu button.
tabindex="-1" ul
  • Allows DOM focus to be set on the menu container with the JavaScript focus method.
  • Dynamically added by the JavaScript.
  • Note that users never perceive the menu container as focused. When the menu is open, only menu items are perceived as focused.
aria-activedescendant="IDREF" ul
  • Refers to the descendant menuitem element that is visually indicated as focused.
  • The IDREF value is updated when keys that move the focus indicator among menu items are pressed.
  • Enables assistive technologies to know which element the application regards as focused while DOM focus remains on the ul element with role menu.
  • For more information about this focus management technique, see Using aria-activedescendant to Manage Focus.
menuitem li
  • Identifies the li element as a menuitem.
  • The text content of the li element provides the accessible name of the menuitem.

Javascript와 CSS 소스 코드

HTML Source Code