Browser widget and PDFs

[hh]

If the PDF is embedded by ordinary HTML (= set url of the
browser widget or use in its htmlText <embed>, <iframe> or
<object>) then you can't decide for the user which plugin
to use.

But the user can force this for himself by moving the
corresponding plugin(s) in/out of the plugins-folder
(which is on Mac "/Library/Internet Plug-ins").

Controlling is fully possible because the user cannot
disable JavaScript for the browser widget. So you can
use the rendering library "pdf.js":
https://mozilla.github.io/pdf.js/
(which drives the Firefox and Opera PDF-viewer).
This isn't easy to implement if CORS isn't available, but
you can use base64-encoded data URLs without problems.