The zero-width space , abbreviated ZWSP, is a
non-printing character
In computing and telecommunication, a control character or non-printing character (NPC) is a code point (a number) in a character set, that does not represent a written symbol. They are used as in-band signaling to cause effects other than the ...
used in computerized
typesetting to indicate word boundaries to text-processing systems in scripts that do not use explicit spacing, or after characters (such as the
slash) that are not followed by a visible
space but after which there may nevertheless be a
line break. It is also used with languages without visible space between words, for example,
Japanese. Normally, it is not a visible separation, but it may expand in passages that are fully
justified.
Usage
In
HTML pages, the zero-width space can be used to mark a potential line break ''without''
hyphenation, as can the HTML element
<wbr>; for hyphenated line breaks, a
soft hyphen is used. The zero-width space was not supported in some older
web browsers.
To show the effect of the zero-width space, the following words have been separated with zero-width spaces:
And the following words are not separated with these spaces:
On browsers supporting zero-width spaces, resizing the window will
re-break the first text only at word boundaries, while the second text will not be broken at all.
Prohibited in URLs
ICANN
The Internet Corporation for Assigned Names and Numbers (ICANN ) is an American multistakeholder group and nonprofit organization responsible for coordinating the maintenance and procedures of several databases related to the namespaces ...
rules prohibit
domain names from including non-displayed characters such as zero-width space, and most browsers prohibit their use within domain names because they can be used to create a
homograph attack, where a malicious URL is visually indistinguishable from a legitimate one.
Encoding
The zero-width space character is encoded in
Unicode as , and input in HTML as , or . Contrary to what their names suggest, the character entities
​,
​,
​, and
​ also refer to the zero-width space.
The
TeX representation is ; the
LaTeX representation is
\hspace; and the
groff representation is
\:.
Its semantics and
HTML implementation are similar to the soft hyphen, except that soft hyphens display a hyphen character at the point where the line is broken.
See also
*
Hair space
In computer programming, whitespace is any character or series of characters that represent horizontal or vertical space in typography. When rendered, a whitespace character does not correspond to a visible mark, but typically does occupy an area ...
*
Whitespace character – including a table comparing various space-like characters
*
Word divider
*
Word wrapping
*
Word joiner (U+2060: ), as well as ''zero-width no-break space'' (U+FEFF: )
*
Zero-width joiner (U+200D: )
*
Zero-width non-joiner (U+200C: )
References
Citations
Sources
*
Unicode Consortium,
Special Areas and Format Characters (Chapter 16), ''The Unicode Standard'', Version 5.2.
*
Victor H. Mair, Yongquan Liu, ''Characters and computers'', IOS Press, 1991.
{{DEFAULTSORT:Zero-Width Space
Control characters
Typography
Unicode formatting code points
Whitespace