The IDREF value is updated when keys that move the focus indicator among menu items are pressed.Refers to the descendant menuitem element that is visually indicated as focused.When the menu is open, only menu items are perceived as focused.
Note that users never perceive the menu container as focused.Allows DOM focus to be set on the menu container with the JavaScript focus method.The menu is labeled by the menu button.Refers to the element that contains the accessible name for the menu.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. 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.
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.
When an element loses focus, its border changes from 3 pixels to 1 and padding is increased by 2 pixels. When an element receives focus, its border changes from 1 to 3 pixels and padding is reduced by 2 pixels. Instead of using transparency, the focused element has a thicker border and less padding.