This is a Pjax-tutorial. Pjax is a standalone JavaScript module that uses ajax (XmlHttpRequest) and pushState() to deliver a fast browsing experience.
To run this tutorial, clone it into your system and simply run the following commands -
npm install
npm run tutorial
To read about Pjax and learn how to implement it yourself, have a look at my blog - http://blog.knoldus.com/2017/11/13/pjax-loading-your-website-faster/
Pjax github repository - https://github.com/MoOx/pjax