Zero-width space

The zero-width space (rendered: ​; HTML entity: ​ or ​), abbreviated ZWSP, is a 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 breaks appropriately.

The zero-width space is Unicode character U+200B, and is located in the Unicode General Punctuation block. In HTML, it can be represented by the character entity reference ​.

Purpose

The zero-width space marks a potential line break without hyphenation. Its semantics and 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, Myanmar, Khmer, and Japanese.^[1]

In 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.^[1]

Example

To show the effect of the zero-width space in text, the following words have been separated with zero-width spaces:

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

By contrast, the following words have not been separated:

LoremIpsumDolorSitAmetConsecteturAdipiscingElitSedDoEiusmodTemporIncididuntUtLaboreEtDoloreMagnaAliquaUtEnimAdMinimVeniamQuisNostrudExercitationUllamcoLaborisNisiUtAliquipExEaCommodoConsequatDuisAuteIrureDolorInReprehenderitInVoluptateVelitEsseCillumDoloreEuFugiatNullaPariaturExcepteurSintOccaecatCupidatatNonProidentSuntInCulpaQuiOfficiaDeseruntMollitAnimIdEstLaborum

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

Usage

HTML

In HTML pages, the HTML element <wbr> functions as a zero-width space. In Internet Explorer 6, the zero-width space was not supported in some fonts.^[2]

Unspecific use

The zero-width space should not be used to prevent automatic conversion of certain character combinations into emojis, because it marks a line break opportunity.^{[note 1]} To prevent systems from converting sequences like :) into emoji like ☺ or 🙂, the zero-width non-joiner or any other non-breaking non-displayed character should be used.^{[3][note 2]}

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 homograph attack, where a malicious URL is visually indistinguishable from a legitimate one.^[4][5]

Encoding

The zero-width space character is encoded in Unicode as U+200B ZERO WIDTH SPACE.^[6]

In HTML, it can be referenced as ​, ​ or ​. Additionally, the character entities ​, ​, ​, and ​ all also refer to the zero-width space, contrary to what their names suggest.^[7]

In HTML 'mailto:' tags^[clarify], %E2%80%8B renders a zero-width space (but may interfere with correctly copying the email link).

The TeX representation is \hskip0pt; the LaTeX representation is \hspace{0pt};^[8] and the groff representation is \:.^[9]

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: )
• Zero-width joiner (U+200D: ‍)
• Zero-width non-joiner (U+200C: ‌)