public function export_data($data = array())     {         # code...         include_once(APP_PATH.'Tools/PHPExcel/Classes/PHPExcel/Writer/IWriter.php') ;         include_once(APP_PATH.'Tools/PHPExcel/Classes/PHPExcel/Writer/Excel5.php') ;         include_once(APP_PATH.'Tools/PHPExcel/Classes/PHPExcel.php') ;         include_once(APP_PATH.'Tools/PHPExcel/Classes/PHPExcel/IOFactory.php') ;         $obj_phpexcel = new PHPExcel();         $obj_phpexcel->getActiveSheet()->setCellValue('a1','Key');         $obj_phpexcel->getActiveSheet()->setCellValue('b1','Value');                if($data){             $i =2;             foreach ($data as $key => $value) {                 # code...                 $obj_phpexcel->getActiveSheet()->setCellValue('a'.$i,$value);                 $i++;             }         }            $obj_Writer = PHPExcel_IOFactory::createWriter($obj_phpexcel,'Excel5');         $filename = "outexcel.xls";         header("Content-Type: application/force-download");         header("Content-Type: application/octet-stream");         header("Content-Type: application/download");         header('Content-Disposition:inline;filename="'.$filename.'"');         header("Content-Transfer-Encoding: binary");         header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");         header("Cache-Control: must-revalidate, post-check=0, pre-check=0");         header("Pragma: no-cache");         $obj_Writer->save('php://output');     }