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Character reference

A character reference is a small piece of code used to represent some characters in HTML documents. Mainly used to insert symbols that don't belong to the document's character encoding (or, in many cases, symbols that are hard to input), character references can be inserted using a regular expression. In fact, each character reference can be inserted in three different ways:

• By its entity name: Every character reference has an entity asigned. The format to insert a symbol by its entity name is composed by an ampersand symbol ("&") followed by the entity name and a semicolon (";"). For example, the pound symbol ("£") can be encoded as "£".
• By its decimal value: As well as with entities, a unique number is asociated with each character reference. The format is composed by the ampersand symbol ("&") followed by the numeral symbol ("#"), the asociated number and a semicolon (";"). For example, the pound symbol ("£") is encoded as "£".
• By its hexadecimal value: This is exactly as the decimal notation with the difference that the number is in hexadecimal format and a lowercase "x" letter is added after the umeral symbol ("#"). Letters in the hexadecimal numbers must be uppercase. For example, the code for the pound symbol ("£") is "£".

Many browsers don't provide support for all character entities and they usually render a white square ("□") or a question mark ("?" or "�") instead. On the other hand, the hexadecimal notation for character references is not supported by many browsers, making of it a poorly fiable way of reproducing symbols. With this said, it becomes clear that the better way to represent character references is using the decimal notation.

Character reference tables

Below are three lists of character references showing all three ways to write them and the representation of each symbol available for HTML documents. XHTML documents include the apostrophe symbol, refered as "'" (by its entity name), "'" (by its decimal value) and "&#x27" (by its hexadecimal value).

Note that, as this character reference has been recently introduced, many browsers still can't process it by its entity name, so the decimal representation is the most recommended.

Markup-significant and internationalization

ISO 8859-1 (Latin 1)

Symbols, mathematical symbols, and Greek letters