I would to add row values in an array each column will be an array value.
echo '<table>' . "\n";
for ($row = 1; $row <= $highestRow; ++$row) {
echo '<tr>' . "\n";
for ($col = 0; $col <= $highestColumnIndex; ++$col) {
$values = '<td>' . $objWorksheet->getCellByColumnAndRow($col, $row)->getValue() . '</td>' . "\n";
$items[]=$values;
}
echo '</tr>' . "\n";
}
echo '</table>' . "\n";