Web Design in a Nutshell, 3rd Edition

Character Sets and Encoding

The first challenge in internationalization is dealing with the staggering number of unique character shapes (called glyphs ) that occur in the writing systems of the world. This includes not only alphabets, but also all ideographs (characters that indicate a whole word or concept) for such languages as Chinese, Japanese, and Korean. There are also invisible characters that indicate particular functionality within a word or a line of text, such as characters that indicate that adjacent characters should be joined.

To understand character encoding as it relates to HTML, XHTML, and XML, you must be familiar with some basic terms and concepts.

Character set

A character set is any collection or repertoire of characters that are used together for a particular function. Many character sets have been standardized, such as the familiar ASCII character set that includes 128 characters mostly from the Roman alphabet used in modern English.

Coded character set

When a specific number is assigned to each character in a set, it becomes a coded character set. Each position (or numbered unit) in a coded character set is called a code point (or code position ). In Unicode, (discussed in more detail later) the code point of the greater-than symbol (>) is 3E in hexadecimal or 62 in decimal. Unicode code points are typically denoted as U+hhhh, where hhhh is a sequence of at least four and sometimes six hexadecimal digits.

Character encoding

Character encoding refers to ...