Cache, Cookies, and History, Oh, My!

Cache, Cookies, and History, Oh, My!

The internet’s come a long way in its short lifetime. The sophisticated images, interactivity, and videos we have now were just imaginings ten years ago. There’s a lot of magic going on in the background of a browser that makes these features possible. To do this programmers and marketers are challenged: how do we make our web page load faster and how do we make our website experience the best.


One way developers speed up how fast web pages load is to use the cache. This is a place in your computer’s memory where basic elements of a web page are saved. Then, anytime you revisit the same web page, the basic features of the web page are immediately accessible from your own computer so the page loads faster.

Files saved in cache.
My cache currently has over 10,000 files totaling 349 megabytes.

You can picture the things saved in cache for a single web page as a stencil. It takes a lot of time to carefully design and cut a stencil. But the next time you want to repeat the design, you don’t have to recreate the stencil, you simply trace it and customize as desired.


Cookies are a way websites allow you to customize a web page to a particular computer and/or user. A web page can create cookies to save your user id, password, custom news feeds, zip code, color settings, and whether you opt-in to or take advantage of special offers.

The keeps track of the cities I’ve looked at the weather for.

Cookies can get very sophisticated so let’s look at a basic example. is giving away a free game download ‘per person’. On your home computer you go to and click the download button and the game is saved on your machine. You close the browser and shut down your machine for the day.

The next day you go to again but the download button is gone. It knows you downloaded the game because when you clicked the download button the first time, the code for the web page saved a cookie on your machine saying it did so (something simple like “ABCgame_free_download = TRUE”).

Then you go to your mom’s and she wants the game. You go to on her computer and the download button appears. How?

Unless a website requires you to register and create an account first, a computer can’t differentiate which human is sitting at the computer. A website can only differentiate between computers. So when you go to on your mom’s computer, the code for the website looks for the cookie (“ABCgame_free_download”) on her computer and doesn’t find it.


Unless the feature is disabled, a browser keeps a chronological list of every web page you visit. This is called the browser History. The Back or Forward buttons on your browser uses this chronology to perform the Back and Forward functions.

Back and Forward buttons on the Chrome browser
The Back and Forward buttons found in the upper left corner on the Chrome browser.

A browser also lets you view your History which is extremely helpful in finding that thing you saw that day on that web page that you can’t remember.  If anyone else uses your computer, they can also look through your surfing history and get a pretty accurate picture of your browsing habits. Think about it.

Firefox history page
The full history page in Firefox.

The amount of History saved by a browser has a cutoff but, by default, it’s pretty generous.

Chrome app icon  Chrome keeps 90 days of history.

  Firefox keeps history from the very first time you used the browser. (My FF has history from December 2014 when I bought the computer.)

IE app icon  Internet Explorer keeps 20 days by default. You can change this to a range from 0 to 999.

Safari app icon  Safari keeps history for 1 year. You have the option to change this from 1 day to always.

Can You Prevent Web Sites From Saving This Stuff?

Yes, but that’s a topic for another post. Each browser is different and typically does not make it easy to disable. Browsers are in competition to provide users with the most sophisticated internet experience by accommodating the latest multi-media technology. Cache, cookies, and history are data and data is marketing currency.

I’ll Give You a Topic

Are you at all concerned about what this data collection is doing to privacy issues or do you think the information collected is rather benign?


Rhonda has a BS in Mathematics and Computer Science and is a self-taught graphic designer. She considers herself a geek*wildcard because she has a little bit of experience in everything.


    1. Author

      Thanks Andrew. Let me know if there’s anything you’d like me to cover in future articles.

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