E-Signature with pki.js and mozilla pdf.js

https://pkijs.org/

PKI.js

PKIjs is a pure JavaScript library implementing the formats that are used in PKI applications (signing, encryption, certificate requests, OCSP and TSP requests/responses). It is built on WebCrypto (Web Cryptography API) and requires no plug-ins.

Some examples:

https://pkijs.org/#examples

Signature verification and PDF sign example:

https://pkijs.org/examples/PDFexample.html

https://mozilla.github.io/pdf.js/

PDF.js

A general-purpose, web standards-based platform for parsing and rendering PDFs.

https://github.com/mozilla/pdf.js/issues/4743

We have implemented both signing and signature verification of PDFs in browser using https://pkijs, you can see an early signature verification demo here: https://pkijs.org/examples/PDFexample.html we have not yet integrated with PDFjs but will be doing that in the not so distant future. Our intention is to release most of this as OSS and give back any changes to PDFjs that are necessary to make integration smooth.