Character Entity References
Characters not found in the normal alphanumeric character set, such as < and &, must be specified in HTML and XHTML documents using character references . This is known as escaping the character. Using the standard desktop publishing keyboard commands (such as Option-G for the © symbol) within an HTML document will not produce the desired character when the document is rendered in a browser. In fact, the browser generally displays the numeric entity for the character.
In (X)HTML documents, escaped characters are indicated by character
references that begin with &
and
end with ;
. The character may be
referred to by its Numeric Character Reference (NCR) or a predefined character entity name.
A Numeric Character Reference refers to a character by its Unicode
code point in either decimal or hexadecimal form (for more information on
Unicode and code points, see Chapter
6). Decimal character references use the syntax &#
nnnn
;
. Hexadecimal values are indicated by an “x”:
&#
xhhhh
;
. For example, the less-than (<)
character could be identified as <
(decimal) or <
(hexadecimal).
Character entities are abbreviated names for characters, such as
<
for the less-than symbol.
Character entities are predefined in the DTDs of markup languages such as
HTML and XHMTL as a convenience to authors, because they may be easier to
remember than Numeric Character References.
Tip
XHTML includes the XML entity declaration for the apostrophe
('
). In HTML, the apostrophe ...
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