answering the questions 18

Dear sir,

I need the answer of two questions below.

Fetching something over the network is both slow and expensive. Large responses require many roundtrips between the client and server, which delays when they are available and when the browser can process them, and also incurs data costs for the visitor. As a result, the ability to cache and reuse previously fetched resources is a critical aspect of optimizing for performance.

The good news is that every browser ships with an implementation of an HTTP cache.

Examplain in details the follwoing:

  1. Validating cached responses
  2. Cache-Control and Cache-Control policy