Non-breaking space

In word processing and digital typesetting, a non-breaking space (" ") (also called no-break space, non-breakable space (NBSP), hard space, or fixed space) is a space character that prevents an automatic line break at its position. In some formats, including HTML, it also prevents consecutive whitespace characters from collapsing into a single space.

In HTML, the common non-breaking space, which is the same width as the ordinary space character, is encoded as   or  . In Unicode, it is encoded as U+00A0.

Non-breaking space characters with other widths also exist.

Uses and variations

Despite having layout and uses similar to those of whitespace, it differs in contextual behavior.

Non-breaking behavior

Text-processing software typically assumes that an automatic line break may be inserted anywhere a space character occurs; a non-breaking space prevents this from happening (provided the software recognizes the character). For example, if the text "100 km" will not quite fit at the end of a line, the software may insert a line break between "100" and "km". To avoid this undesirable behaviour, the editor may choose to use a non-breaking space between "100" and "km". This guarantees that the text "100 km" will not be broken: if it does not fit at the end of a line it is moved in its entirety to the next line.

Character encodings in HTML

HTML (Hypertext Markup Language) has been in use since 1991, but HTML 4.0 (December 1997) was the first standardized version where international characters were given reasonably complete treatment. When an HTML document includes special characters outside the range of seven-bit ASCII two goals are worth considering: the information's integrity, and universal browser display.

Specifying the document's character encoding

There are several ways to specify which character encoding is used in the document. First, the web server can include the character encoding or "charset" in the Hypertext Transfer Protocol (HTTP) Content-Type header, which would typically look like this:

This method gives the HTTP server a convenient way to alter document's encoding according to content negotiation; certain HTTP server software can do it, for example Apache with the module mod_charset_lite.

For HTML it is possible to include this information inside the head element near the top of the document: