One way of outputting a webpage to mPDF without re-writing your scripts too much, is to buffer the output:
<?php// Require composer autoloadrequire_once__DIR__.'/vendor/autoload.php';$mpdf=new\Mpdf\Mpdf();// Buffer the following html with PHP so we can store it to a variable laterob_start();// This is where your script would normally output the HTML using echo or printecho'<div>Generate your content</div>';// Now collect the output buffer into a variable$html=ob_get_contents();ob_end_clean();// send the captured HTML from the output buffer to the mPDF class for processing$mpdf->WriteHTML($html);$mpdf->Output();