Codeigniter excel编码问题

I have downloaded php excel exporter library from http://phpexportxlsclass.googlecode.com/files/export-xls.class-v1.01.zip

It works fine if I run demo.php file independantly from the zip.

I have included export-xls.class.php file in libraries folder and called that library from controller

here is the code snippet

function export_to_excel() {

    require(APPPATH.'libraries/exportxls.php');

    $config['filename'] = 'test1.xls'; // The file name you want any resulting file to be called.
    $xls = new ExportXLS($config);

    $xls->addHeader("Test Spreadsheet");
    $xls->addHeader(null);
    $header = array("Name", "Age", "Height");
    $xls->addHeader($header);
    $row = array();
    $row[] = array('Jack', '24', '6ft');
    $row[] = array('Jim', '22', '5ft');
    $row[] = array('Jess', '54', '4ft');
    $row[] = array('Luke', '6', '2ft');
    $xls->addRow($row);
    $xls->sendFile();
}

but when I run my code using url http://www.domain.com/controller/export_to_excel then it will give me following excel file as an output.

For windows support: add these line in private function textFormat($row, $col, $data)

iconv("UTF-8", "CP1252", $data);

see this for more discussion on this issue.