[ Ahuka Home Page | HTML Level 1 Main Page | ISO Entities ]

ISO Entities

When you create an electronic text file of any kind, you may be typing letters, but the file does not contain letters. No computer file does that. It stores zeroes and ones in a complex code that a piece of software can read and then translate into the characters you see when the file is opened and displayed. The way this looks when it is displayed depends on two different pieces of information. The first is the character code, and the second is the font. In a word processor you can do some fancy things this way using unusual fonts like WingDings, but in the Web environment font choices are somewhat more limited, which is why people don't use fonts like WingDings for Web pages, if they are smart. Wingdings is Windows-only font, so it would not be available for a large number of browsers.

In a pure text environment, like ASCII text, no font information is used at all. But there are still a number of characters available. In the ASCII coding scheme, an 8-bit byte is used to code each character. Since each bit can be either a zero or a one, 8 bits means you can have 2^8 = 256 possible characters. The way these codes are used has been standardized by the International Organization for Standardization (ISO) for various languages. A good Web editor will declare the language you are using in the head section using a META tag like this:

<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">

This says that the character set being used in the document is the ISO-8859-1 character set, which is the Latin-1 set used by many Western European languages. Other languages use other character sets as needed, which is how Russian, Greek, etc. pages can be created.

The ISO-8859-1 character set has 256 possible characters, in theory, numbered from 0 to 255. Any of these characters can be used in a Web page by first using the escape character, the Ampersand (&), followed by the number (with a # sign in front), and finally a semicolon (;). The Ampersand is the signal to the browser that something different is going to happen, and that it should not display the characters that folllow, but instead treat them as a special code. The semicolon at the end tells the browser that the special code is finished, and that it should resume displaying the characters that it finds in the text.

Your keyboard handles a lot of this stuff for you. When you type on it, it sends the numerical code for your letters, punctuation, etc. and the software displays it just fine. So while anything you can type on a keyboard has a numerical code, in practice you never need to think about it. It is only when you need a special character that is not on the keyboard that you need to know the code. Here are the ISO-8859-1 entities:

*Note 1: The first 32 characters (0-31) are non-printing control characters reserved since the dark ages for really geeky computer science stuff, like controlling line printers attached to mainframe computers. There is no reason I can think of why they need to be reserved in the ISO-8859-1 character set, other than inertia, but in any case they are still reserved for these reasons. If you want to see what they are, go to

http://daffy.robelle.com/smugbook/ascii.html

**Note: In the last column are text equivalents for many of the numerical codes. Support for some of these is not as great as for the numerical codes.