Control of requested files, how to?

Question

while playing with a Phalcon tutorial I observed that when navigating it only made one get file request from server event if where inluded more files in HTML.

http://188.240.2.29:20005/ if you navigate between menus one GET is made only, when refresh page with F5 additional files are called.

Same thing i observed with other websites: StackOverflow has 9 files called while with F5 there are 29, Reddit normally has 15 files called wile with F5 refresh 35 files are called.

I want to know how this is achieved and how it can be implemented in other websites.

Answer 1

Isn't about Phalcon itself, but it's about HTTP Cache. You can read more about it and learn how to implement it here, here and here.