php将页面转换为带有id的pdf加载

我有来自MySQL DB的动态加载,我的页面URL是http:// localhost/far/contractview？ID = 137.当我尝试将此页面转换为PDF时,我遇到了一些错误,我不知道如何处理,只需按一下按钮即可将此页面转换为PDF.

我在下面提供了我的代码.我在用mpdf.

debug = true;
//$mpdf->allow_output_buffering = true;
//$mpdf->SetHeader('|Your Header here|');
//$mpdf->setFooter('{PAGENO}');// Giving page number to your footer.
$mpdf->useOnlyCoreFonts = true;    // false is default
$mpdf->SetDisplayMode('fullpage');
// Buffer the following html with PHP so we can store it to a variable later
ob_start();
?>

WriteHTML($html);
//$mpdf->SetProtection(array(), 'user', 'password'); uncomment to protect your pdf page with password.
$mpdf->Output();
exit;
?>

提前致谢.