The zero-width space () (ZWSP) is a non-printing character used in computerized typesetting to indicate word boundaries to text processing systems when using 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.
In HTML pages, the zero-width space can be used as a potential line-break in long words as an alternative to the
<wbr> element. However, the zero-width space is not supported in some web browsers such as old versions of Internet Explorer (versions 6 and earlier).
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.
Blacklisting in URLs
ICANN rules prohibit domain names from including non-displayed characters such as zero-width space, and most browsers blacklist 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.
The zero-width space character is encoded in Unicode as U+200B ZERO WIDTH SPACE (HTML
- "Zones spéciales et caractères de formatage" [Special areas and formatting characters] (PDF). Hapax Quebec (in French). p. 3. Archived from the original (pdf) on 27 December 2015. Retrieved 31 July 2019.
Les espaces sans chasse sont conçues pour les langues qui ne séparent pas les mots à l’aide d’espaces visibles, comme le thaï ou le japonais.
- The Unicode Standard 6.1, p. 366
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