Cookies

Cookies. Not chocolate chip, or oatmeal raisin (my favorite), but web cookies, or persistent cookies, have gotten a bad rap. They are (mostly) relatively harmless. (I say “mostly” because I consider third-party tracking cookies to be not so harmless.)

What are they? Cookies are nothing more than a data key-pair, which are stored in a file on your hard drive. This pair consists of a name for the cookie, and then a value related to that name.
For example:

cookie_for_xyx.com = background_red 

See the How to Use Cookies with Javascript page for a brief tutorial on how to use JavaScript and cookies.

The major issue is that you can visit a web site, and they can store information about you on your computer. The cookie can store any information it wants, but can store only information about you that you give it, such as preferences, or last time you visited that page, or even your name.

The information stored by the server that placed the cookie can only be retrieved by the server that placed it. So if you go to one site, which stores your name in a cookie, no other site can retrieve that cookie, but the site that placed it.

Cookies are helpful to improve your browsing. If you go to a page such as my.yahoo.com, or amazon.com, or any other page that you may personalize, the cookie can save how you like the page, and show it to you that way next time.

Cookies are also used in shopping carts. The server can store your order information in a cookie when you go from page-to-page. So when you finalize your order, it can pull the order up all at once. The information is safe, because only the computer that stored the information can retrieve it.

The cookie specification introduced by Netscape also places limits on cookies. These limits are:

• 300 total cookies.
• 4 kilobytes per cookie, including the name portion.
• 20 cookies per server or domain.

You can view the cookie file that is stored on your hard drive. For Windows running Microsoft or Netscape, the file is called cookies.txt, and should be in the same directory as your browser. The 4.0 versions are making more directories and moving things around a bit, but a quick search should turn it up. On Macintosh computers, I believe the file is called 'magic cookies'.

Also most of the current browsers give you the option to be warned when a cookie is set, and the option not to store any cookies that you are sent.

Related Links:

• Netscape Cookie Specification
• c|net Article regarding Cookie Security
• Cookie Information and Resources
• PC Magazine's Cookie Utilities