Adding an Expires or Cache-Control header (Simple)

Websites usually contain the mixture of static and dynamic elements that are being used uniformly over different pages. When a browser starts loading a web page, it usually downloads all the images, CSS files, JavaScript files, and Flash files, if any. Imagine if every time the browser had to download each and every file associated with that page, how hectic it would be for both the browser and the user, and you would have a bandwidth problem too. Gone are the days when people used few static pages with less creativity. Now, almost all websites contain a lot of JavaScript and CSS scripts; images that make the site a bit slower and heavy.