I have seen some websites that include nice transitions between pages, such as sliding or fading, etc. Most of these I have seen are actually one page that just transitions various sections. Then I came across a website that does it differently.
If you view this site and click the various pages the pages transition smoothly but the URLs are different and it doesn't appear to be one page site with hidden sections.
How is this done? I looked for explanations on how to do this but never found a good answer. Any help in determining how this is done would be great.
Note: I am looking to replicate this feature for websites I build so I am looking for an answer that will explain the idea or process of how this is coded.