View source for Zero-width space

{{Short description|Special character in text processing}}
The '''zero-width space''' (rendered: {{Not a typo|{{kbd|&ZeroWidthSpace;}}}}; [[HTML entity]]: {{kbd|&amp;ZeroWidthSpace;}} or {{kbd|&amp;#8203;}}), abbreviated '''ZWSP''', is a [[control character|non-printing character]] used in computerized [[typesetting]] to indicate where the word boundaries are, without actually displaying a visible space in the rendered text. This enables text-processing systems for scripts that do not use explicit spacing to recognize where word boundaries are for the purpose of handling [[line wrap and word wrap|line breaks]] appropriately.

The zero-width space is [[Unicode character]] <code>U+200B</code>, and is located in the Unicode [[General Punctuation]] block. In HTML, it can be represented by the [[character entity reference]] {{As written|<code>&amp;ZeroWidthSpace;</code>}}.

== Purpose ==
The zero-width space marks a potential line break without [[syllabification|hyphenation]]. Its semantics and [[HyperText Markup Language|HTML]] implementation are similar to the [[soft hyphen]], but soft hyphens display a hyphen character at the point where the line is broken.

The zero-width space can be used to mark word breaks in languages without visible space between words, such as [[Thai language|Thai]], [[Myanmar language|Myanmar]], [[Khmer language|Khmer]], and [[Japanese language|Japanese]].<ref name="Unicode Standard">{{cite book |title=The Unicode® Standard Version 15.0 – Core Specification |date=September 2022 |chapter=23.2 Layout Controls |publisher=The Unicode Consortium |isbn=978-1-936213-32-0 |url=https://www.unicode.org/versions/Unicode15.0.0/UnicodeStandard-15.0.pdf#page=944 |page=918}}</ref>

In [[justification (typesetting)|justified]] text, the rendering engine may add inter-character spacing, also known as letter spacing, between letters separated by a zero-width space, unlike around fixed-width spaces.<ref name="Unicode Standard"/>

=== Example ===
To show the effect of the zero-width space in text, the following words have been separated with zero-width spaces:
<blockquote><div style="background:#f7f7f7; border:solid 1px #CCC; padding:4px;">
{{Zwsp|Lorem|Ipsum|Dolor|Sit|Amet|Consectetur|Adipiscing|Elit|Sed|Do|Eiusmod|Tempor|Incididunt|Ut|Labore|Et|Dolore|Magna|Aliqua|Ut|Enim|Ad|Minim|Veniam|Quis|Nostrud|Exercitation|Ullamco|Laboris|Nisi|Ut|Aliquip|Ex|Ea|Commodo|Consequat|Duis|Aute|Irure|Dolor|In|Reprehenderit|In|Voluptate|Velit|Esse|Cillum|Dolore|Eu|Fugiat|Nulla|Pariatur|Excepteur|Sint|Occaecat|Cupidatat|Non|Proident|Sunt|In|Culpa|Qui|Officia|Deserunt|Mollit|Anim|Id|Est|Laborum}}
</div></blockquote>

By contrast, the following words have not been separated:
<blockquote><div style="background:#f7f7f7; border:solid 1px #CCC; padding:4px;">
{{Not a typo|LoremIpsumDolorSitAmetConsecteturAdipiscingElitSedDoEiusmodTemporIncididuntUtLaboreEtDoloreMagnaAliquaUtEnimAdMinimVeniamQuisNostrudExercitationUllamcoLaborisNisiUtAliquipExEaCommodoConsequatDuisAuteIrureDolorInReprehenderitInVoluptateVelitEsseCillumDoloreEuFugiatNullaPariaturExcepteurSintOccaecatCupidatatNonProidentSuntInCulpaQuiOfficiaDeseruntMollitAnimIdEstLaborum}}
</div></blockquote>

The first text is broken into lines but only at word boundaries, and resizing the browser window will [[Reflowable document|re-break]] the text accordingly, while the second text is not broken at all.

== Usage ==
=== HTML ===
In [[HTML]] pages, the HTML element {{Tag|[[HTML element#wbr|wbr]]|o}} functions as a zero-width space. In [[Internet Explorer 6]], the zero-width space was not supported in some fonts.<ref>{{cite web|url=http://dunae.ca/2009/better-web-typography-with-spaces-and-hyphens/ |first=Alex|last=Dunae |title=Better Web Typography with Spaces and Hyphens |work=dunae.ca |access-date=December 3, 2009 |archive-url=https://web.archive.org/web/20101214223741/http://dunae.ca/2009/better-web-typography-with-spaces-and-hyphens/ |archive-date=December 14, 2010}}</ref>

=== Prohibition in domain names ===
[[ICANN]] rules prohibit [[domain names]] from containing non-displayed characters, including the zero-width space, and most browsers prohibit their use within domain names because they can be used to create a [[IDN homograph attack#Non-displayable characters|homograph attack]], where a malicious URL is visually indistinguishable from a legitimate one.<ref>{{cite web |title=Network.IDN.blacklist_chars |work=mozillaZine |url=http://kb.mozillazine.org/Network.IDN.blacklist_chars |access-date=2018-02-07}}</ref><ref>{{cite web |title=Unicode Character 'Zero Width Space' |work=FileFormat.Info |url=https://www.fileformat.info/info/unicode/char/200b/index.htm |access-date=2018-02-07}}</ref>

== Encoding ==
The zero-width space character is encoded in [[Unicode]] as {{unichar|200B|ZERO WIDTH SPACE}}.<ref>{{cite web| title=General Punctuation – Unicode| url=https://www.unicode.org/charts/PDF/U2000.pdf| access-date=2013-07-20}}</ref>

In HTML, it can be referenced as {{Not a typo|<code>&amp;ZeroWidthSpace;</code>}}, {{Not a typo|<code>&amp;#8203;</code>}} or {{Not a typo|<code>&amp;#x200B;</code>}}. Additionally, the character entities <code>&amp;NegativeThickSpace;</code>, <code>&amp;NegativeMediumSpace;</code>, <code>&amp;NegativeThinSpace;</code>, and <code>&amp;NegativeVeryThinSpace;</code> all also refer to the zero-width space, contrary to what their names suggest.<ref>[https://zvon.org/comp/r/ref-MathML_2.html#Entities~ZeroWidthSpace Entities/ZeroWidthSpace] in MathML Version 2.0</ref>

In HTML <code><nowiki>mailto:</nowiki></code> {{clarify span|tags|Tags? There is mailto URL scheme – did someone mean this?|date=March 2025}}, %E2%80%8B renders a zero-width space (but may interfere with correctly copying the email link).{{citation needed|date=May 2025}}

The [[TeX]] representation is {{Not a typo|<code>\hskip0pt</code>}}; the [[LaTeX]] representation is <code>\hspace{0pt}</code>;<ref>{{cite web| title=The LaTeX Companion. Chapter 3: Basic Formatting Tools| url=https://www.latex-project.org/help/books/bookpart_tlc2-ch3.pdf| access-date=2019-07-16}}</ref> and the [[groff (software)|groff]] representation is <code>\:</code>.<ref>{{cite web| title=groff(7) – Linux manual page| url=http://man7.org/linux/man-pages/man7/groff.7.html| access-date=2014-02-08}}</ref>

== See also ==
* [[Hair space]]
* [[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: )<!--now it's a redirect, so there is no point in linking to it; see also [https://www.fontspace.com/unicode/char/FEFF-zero-width-no-break-space]-->
* [[Zero-width joiner]] (U+200D: ‍)
* [[Zero-width non-joiner]] (U+200C: ‌)<!-- please don't delete the invisible characters given between the colons and parentheses; it's useful to let them be copied from-->

== References ==
=== Citations ===
{{reflist}}

=== Sources ===
{{refbegin}}
* {{citation | first1 = Victor H. | last1 = Mair | authorlink1 = Victor H. Mair | first2 = Yongquan | last2 = Liu | title = Characters and computers | publisher = IOS Press | date = 1991 }}
{{refend}}

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{{Unicode navigation}}

[[Category:Control characters]]
[[Category:Typography]]
[[Category:Unicode formatting code points]]
[[Category:Whitespace]] <!--admittedly there is no space in a ZWS, but it's useful to put it in the category -->