使用contenteditable元素将HTML转换为带有编辑的PDF

I need a way to convert HTML after the user edit the content editable elements to PDF with the user edits.
Please find the below code which convert the HTML page but without the user edits:

include("mpdf60/mpdf.php");
$wide=300;
$hight=300; 
$mpdf=new mPDF('',array($wide,$hight), 0, '', 15, 15, 16, 16, 9, 9);

$mpdf->WriteHTML(file_get_contents('test.html'));
$mpdf->Output();
exit;