title: Modify existing PDF file in browser
body: <p>Is there any JavaScript library that allows to modify PDF file on the client-side (I mean directly in web browser)? I would like to add an QR code into PDF which user puts into browser, but without sending to the server.</p>
  
  <p>I have found <a href="https://github.com/galkahana/HummusJS" rel="noreferrer">https://github.com/galkahana/HummusJS</a>, but it looks like it works only on the server-side in Node.js.</p>
  
  <p>My temporary solution is to read and render PDF into Canvas via <code>https://github.com/mozilla/pdf.js</code>. After that I simply render QR code and save/render result into PDF document via <code>https://github.com/MrRio/jsPDF</code>. </p>
  
  <p>This solution has flaw, because It just prints out an image into PDF. I need to keep the original format of the PDF and just add that QR code on some page in it.</p>
  
  <p>Any suggestions would be help. Thanks.</p>