function tdOver(cell) {
	var tr = cell.parentNode;
	for (var i = 0; i < tr.cells.length; ++i) {
		addClass(tr.cells[i], 'req-highlight');
	}
}

function tdOut(cell) {
	var tr = cell.parentNode;
	for (var i = 0; i < tr.cells.length; ++i) {
		removeClass(tr.cells[i], 'req-highlight');
	}
}