ic | col1headercolspan = 2 | col1 = | col2 = | col3header = | col3 = | col4header =
Abjad | col4 = | col5header =
Abugida | col5 =
HTML and
XML provide ways to reference Unicode characters when the characters themselves either cannot or should not be used. A
numeric character reference refers to a character by its
Universal Character Set/
Unicode code point, and a
character entity reference refers to a character by a predefined name. A
numeric character reference uses the format :&#
nnnn; or :&#x
hhhh; where
nnnn is the code point in
decimal form, and
hhhh is the code point in
hexadecimal form. The
x must be lowercase in XML documents. The
nnnn or
hhhh may be any number of digits and may include leading zeros. The
hhhh may mix uppercase and lowercase, though uppercase is the usual style. In contrast, a
character entity reference refers to a character by the name of an
entity which has the desired character as its
replacement text. The entity must either be predefined (built into the markup language) or explicitly declared in a
Document Type Definition (DTD). The format is the same as for any entity reference: :&
name; where
name is the case-sensitive name of the entity. The semicolon is required. Because numbers are harder for humans to remember than names, character entity references are most often written by humans, while numeric character references are most often produced by computer programs. == Control codes ==