A sane way of creating excel files inside PHP - requires the PHPExcel library

gistfile1.php

<?php
function wf_fbc_create_and_send_excel_spreadsheet_to_browser( $headings, $data ) {
  ini_set('include_path', ini_get('include_path'). PATH_SEPARATOR . dirname( __FILE__) . '/lib/phpexcel/Classes/');
	include 'PHPExcel.php';
	include 'PHPExcel/Writer/Excel5.php';
	$objPHPExcel = new PHPExcel();
	$objPHPExcel->setActiveSheetIndex(0);
	$objPHPExcel->getDefaultStyle()->getFont()->setName('Times New Roman');
	$objPHPExcel->getDefaultStyle()->getFont()->setSize(10);
	$objPHPExcel->getActiveSheet()->getStyle('1')->applyFromArray(array( 'font' => array('bold' => true,),));
	foreach ( $headings as $i => $heading ) {
		$objPHPExcel->getActiveSheet()->setCellValueByColumnAndRow($i, 1, $heading);
	}

	foreach ( $data as $i => $row ) {
		if ( 0 == ($i+2) % 2 ) {
			$objPHPExcel->getActiveSheet()->getStyle( $i+2 )->applyFromArray(array(
				'fill' => array(
					'type' => PHPExcel_Style_Fill::FILL_SOLID,
					'startcolor' => array( 'argb' => 'FFF0F0F0', )
				),
			) );
		}

		foreach ( $row as $j => $value ) {
			$objPHPExcel->getActiveSheet()->setCellValueByColumnAndRow( $j, $i+2, $value );
		}
	}

	$objWriter = new PHPExcel_Writer_Excel5($objPHPExcel);
	$objWriter->save('php://output');
}