teste09.js

function onLoad(event) {
    var grid = document.getElementById("accessibleGrid");
    grid.currentRow = 0;
    grid.currentCol = 0;
    updateGrid(grid, function() {});
    grid.addEventListener("keydown", onKeyDown, false);
}

function updateGrid(grid, updateFunction) {
    grid.tBodies[0].rows[grid.currentRow].cells[grid.currentCol].className = "";
    updateFunction.call();
    var currentCell = grid.tBodies[0].rows[grid.currentRow].cells[grid.currentCol];
    grid.setAttribute("aria-activedescendant", currentCell.id);
    currentCell.className = "current";
}

function onKeyDown(event) {
    var keyCode = event.keyCode;
    var target = event.currentTarget;

    switch (keyCode) {
    case event.DOM_VK_DOWN:
        if (target.currentRow + 1 < target.tBodies[0].rows.length) {
            updateGrid(target, function() { ++target.currentRow; });
        }
        break;
    case event.DOM_VK_UP:
        if (target.currentRow - 1 > -1) {
            updateGrid(target, function() { --target.currentRow; });
        }
        break;
    case event.DOM_VK_RIGHT:
        if (target.currentCol + 1 < target.tBodies[0].rows[0].cells.length) {
            updateGrid(target, function() { ++target.currentCol; });
        }
        break;
    case event.DOM_VK_LEFT:
        if (target.currentCol - 1 > -1) {
            updateGrid(target, function() { --target.currentCol; });
        }
        break;
    }
}