The zero-width space, 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. Zero-width space is unicode character U+200B, and is located in the unicode General Punctuation block, and can be represented by numeric character references or .
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]
To show the effect of the zero-width space in text, the following words have been separated with zero-width spaces:
By contrast, the following words have not been separated:
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.
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]
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.[3] [4]
The zero-width space character is encoded in Unicode as,[5] and input in HTML as, or . Contrary to what their names suggest, the character entities &NegativeThickSpace;, &NegativeMediumSpace;, &NegativeThinSpace;, and &NegativeVeryThinSpace; also refer to the zero-width space.[6]
The TeX representation is ; the LaTeX representation is \hspace{0pt};[7] and the groff representation is \:.[8]