grid constant
A grid is an interactive control which contains cells of tabular data arranged in rows and columns, like a table.
Grids do not necessarily imply presentation. The grid construct describes relationships between data such that it may be used for different presentations. Grids allow the user to move focus between cells using two dimensional navigation. For example, grid might be used as the invisible data model (hidden with CSS but still operable by assistive technologies) for a presentational chart.
Authors MUST ensure that elements with role gridcell are owned by elements with role row, which in turn are owned by an element with role rowgroup, grid or treegrid. If the author applies any non-global WAI-ARIA states or properties to a native markup element that is acting as a row (such as the tr element in HTML), the author MUST also apply the role of row, as stated in the section on Implementation in Host Languages. Authors MAY make cells focusable. Authors MAY provide row and column headers for grids, by using rowheader and columnheader roles.
Since WAI-ARIA can augment an element in the host language, grids can reuse existing functionality of native table grids. When WAI-ARIA grid or gridcell roles overlay host language table elements they reuse the host language semantics for that table. For instance, WAI-ARIA does not specify general attributes for gridcell elements that span multiple rows or columns. When the author needs a gridcell to span multiple rows or columns, use the host language markup, such as the colspan and rowspan attributes in HTML.
Authors MAY determine the contents of a gridcell through calculation of a mathematical formula. Authors MAY make a cell's formula editable by the user. In a spreadsheet application for example, the text alternative of a cell may be the calculated value of a formula. However, when the cell is being edited, the text alternative may be the formula itself.
gridcell elements with the aria-selected attribute set can be selected for user interaction, and if the aria-multiselectable attribute of the grid is set to true, multiple cells in the grid may be selected. Grids may be used for spreadsheets like those in desktop spreadsheet applications.
A grid is considered editable unless otherwise specified. To make a grid read-only, set the aria-readonly attribute of the grid to true. The value of the grid element's aria-readonly attribute is implicitly propagated to all of its owned gridcell elements, and will be exposed through the accessibility API. An author may override an individual gridcell element's propagated aria-readonly value by setting the aria-readonly attribute on the gridcell.
To be keyboard accessible, authors SHOULD manage focus of descendants for all instances of this role, as described in Managing Focus.
See: developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Roles/grid_role
Implementation
static const String grid = 'grid';