Download address: http://mozilla.github.io/pdf.js/
The above address can be downloaded to the compiled compressed package of about 2.6MB.
github address: https://github.com/mozilla/pdf.js/
The above address can only be downloaded to the development package, and there are also compiled compressed packages, but the whole package is very large.
Because the two addresses are foreign, it may require a wall, or the download is very slow, so I put the simplified compressed package in the attachment.
The usage is very simple, as long as you put the entire directory in the website directory and access the path of the viewer.html?file=pdf file in the web, you can do it. There is no need to integrate it yourself, or rewrite the code or something.