by David Hockenbroch

Created on: December 12, 2008

Remember this sequence: 1248. Now, without looking back, repeat those numbers. Congratulations! You just used your own cache.

Your web browser's cache is a form of temporary memory that it uses to retrieve information more quickly, much like your own short-term memory. When you visit a website, the browser will store a temporary copy of that file in the cache. Then, if you go to the same website again shortly after that, your computer will check to see if the page has changed. If it hasn't, rather than take the time to retrieve the information from the server that the document is on again, your computer will load the document from its cache. It works just like your ability to recall a simple sequence of numbers without rereading it.

Your browser may also cache document associated with the website. For example, many websites use external cascading style sheets, which are documents that tell the browser what certain parts of a webpage should look like. Your browser may cache these as well. In that case, if you go to another page on the same website and it uses the same style sheet, the browser will have to download the new page from the server, but it won't have to download the same style sheet again. The same is true for content such as images or other external files, such as files that contain information that tells a browser what should happen when you click on a certain button or perform some other similar action.

The browser cache serves a few purposes. First, it speeds up your web surfing experience. Downloading files from a server is the most time-consuming process involved between you and the content you want to see. Using these temporary copies, the downloading can be skipped and the pages can be loaded from your computer, saving a lot of time.

Second, the browser cache reduces the amount of bandwidth you are using. Some Internet service providers charge the user based on the amount of data they download each month. Some have a limit on how much you can download. Since the browser cache reduces the number of downloads, it also reduces these numbers and, consequently, your bill if your service provider uses such a pricing scheme.

Finally, the browser cache benefits the websites themselves. Since the cache allows you to view websites without downloading the same information repeatedly from the server, the server has less work to do. This means that the people hosting the website will be saving money, since they won't have to spend as much to host the website.

Overall, the browser cache works a lot like your own short-term memory to save you time, and perhaps some money.

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