How to download a pdf book from a browser?

Question

Browsers

Good afternoon!
The bottom line is this, there is a book in pdf format, but access to it is only through a browser. In what ways and means can you save this book to your PC. The Ctrl+P and Ctrl+S keys do not help, only one page is printed. In the browser print and save as pdf the result is the same. Maybe someone knows and will tell you how to be? I really need this book.

Answer 1

For chrome
F12 further down the picture

Answer 2

Study the requests that the browser issues when displaying a book, write a script that will download it page by page and glue it into one file.

Answer 3

script can be downloaded.
using jQuery to load the content of the entire book on one page.
you may need an iframe to select only the blocks you need.
It is faster to write the code yourself than to look for something ready in the internet.