We'll start off with client-side caching, because it's the easiest to understand and you're probably already fairly familiar with it. There's no doubt that at some point someone has asked you to—clear your cache. When someone says that, they're referring to your web browser's cache. Every web browser has some method for clearing the cache.
Often, client-side caching is defined via special meta
tags in your website's HTML or via a special module for the Apache web server. Both cases control caching with the Cache-Control HTTP Headers.
Since client-side caching isn't really within the scope of this book, I'd like to move on to server-side caching. If you want to learn more about client-side caching, I suggest reading Caching Tutorial for Web Authors and Webmasters; it is available at the following link: