title: Setting custom headers in PDF.JS requests
body: <p>By Default <code>Pdf.js</code> library <a href="https://mozilla.github.io/pdf.js/" rel="nofollow noreferrer">https://mozilla.github.io/pdf.js/</a> does not set <code>X-Requested-With</code> headers needed to identify if incoming request is ajax or not, I needed it to add in my application for some reasons.</p>