带有图表的PHPExcel HTML编写器

I can see a chart in excel generated by PHPExcel, but when i save it to HTML (using HTML Writer) I can't see the chart. how to make the chart work in HTML Version?

here is my code when saving to HTML.

$writer = PHPExcel_IOFactory::createWriter($xls, 'HTML');
$writer->setIncludeCharts(TRUE);
$tmpfile = TEMPFILE;
$writer->save($tmpfile);

echo file_get_contents($tmpfile);