PDF.js is a Portable Document Format (PDF) library that is built with HTML5. Its goal is to create a general-purpose, web standards-based platform for parsing and rendering PDFs.
This is a pre-built version of the PDF.js source code. I was unable to find an ES5 distribution of PDF.js that was both minified and included the viewer.html component. This is essentially just the files produced by running: gulp minified-es5 against the upstream repo.
See https://github.com/mozilla/pdf.js for learning and contributing.