What steps can be taken to ensure the proper functioning of PHPExcel when generating Excel files for download with a specified file format and content type?

To ensure the proper functioning of PHPExcel when generating Excel files for download with a specified file format and content type, you need to set the appropriate headers before outputting the Excel file. This includes setting the content type to "application/vnd.ms-excel" for Excel 2003 format (.xls) or "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet" for Excel 2007+ format (.xlsx), as well as setting the content disposition to "attachment" to trigger a download prompt.

// Set headers for Excel file download
header('Content-Type: application/vnd.ms-excel'); // For Excel 2003 format (.xls)
header('Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet'); // For Excel 2007+ format (.xlsx)
header('Content-Disposition: attachment; filename="example.xlsx"'); // Specify the filename for download

// Output the Excel file
$objWriter = PHPExcel_IOFactory::createWriter($objPHPExcel, 'Excel2007'); // Specify the Excel format
$objWriter->save('php://output');
exit;