public function del_col()
{
try {
$excel = new Excel();
$excel->set_maxcol($excel->get_maxcol() - 1);
$result = array('status' => 'OK', 'msg' => $excel->get_maxcol());
echo json_encode($result);
} catch (Exception $ex) {
$result = array('status' => 'ERROR', 'msg' => $ex->getMessage());
echo json_encode($result);
}
}