>Makes the gridcell focusable and excludes it from the dialog <kbd>Tab</kbd> sequence.</li>
                    <li>Changed dynamically to <code>0</code> by the JavaScript when the gridcell is to be included in the dialog <kbd>Tab</kbd> sequence.</li>
                    <li>At any given time, only one gridcell within the grid is in the dialog <kbd>Tab</kbd> sequence.</li>
                    <li>
                      This approach to managing focus is described in the section on
                      <a h