export function save csv file to a specific folder

You need to write the code that prepares the export file and saves it to some folder on the web server. The article you mentioned provides some pointers.
Besides that you need to make sure that web server user has WRITE permissions on this folder.

thanks
can oyu give more info and links to look and inspire of thanks again

You can find some sample code at http://code.stephenmorley.org/php/creating-downloadable-csv-files/

help please
i see that in export_functions.php
function ExportExcelSave($filename,$format,$objPHPExcel)

{

global $cCharset;

$filename = PHPExcel_Shared_String::ConvertEncoding($filename, 'UTF-8', $cCharset);

if($format == "Excel2007")

header('Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');

else

header('Content-Type: application/vnd.ms-excel');
header('Content-Disposition: attachment;filename="'.now().'";');

header('Cache-Control: max-age=0');
$objWriter = PHPExcel_IOFactory::createWriter($objPHPExcel, $format);

$objWriter->save('php://output');

}
i think i have to change
$objWriter->save('php://output');

to save excel files to my public folder "test"
can you help ?

If you want to modify PHPExcel code check PHPExcel documentation at http://phpexcel.codeplex.com/releases/view/96183