title: mPDF generated PDF is only working in Firefox
body: <p>So I was using the mPDF PHP library to generate a PDF using HTML code. I finished my code and then I realized that it only works in Firefox, for example in Chrome it displays 'Failed to load PDF document'. </p>
  
  <p>Then I used the code from the examples instead of my own code and the same thing happens. Anyone knows how to solve this issue?</p>
  
  <pre><code>&lt;?php
  ob_start();
  include('plugins/mpdf/mpdf.php');
  $mpdf=new mPDF();
  $mpdf-&gt;WriteHTML('&lt;p&gt;Hello World&lt;/p&gt;');
  $mpdf-&gt;Output();
  exit;
  ?&gt;
  </code></pre>