It has been suggested that this article be merged into Underscore. (Discuss) Proposed since October 2013.
An underline, also called an underscore, is one or more horizontal lines immediately below a portion of writing. Single and occasionally double ("double-underscore") underlining was originally used in hand-written or typewritten documents to emphasise text. In a manuscript to be typeset, various forms of underlining were conventionally used to indicate that text should be set in a special typeface such as italics to show emphasis, part of a procedure known as markup. With the advent of word processing, different typefaces can be used in the manuscript directly so that underlining is no longer needed for markup, but underlining is sometimes used in documents in its own right.
Underlines are sometimes used as a diacritic, to indicate that a letter has a different pronunciation from its non-underlined form.
1 Use with computers
1.1 HTML and CSS,
1.2 On Wikis,
1.4 "Simulated" underlines in plaintext,
1.5 As a marker for incorrectness,
2 Underlines in non-Latin scripts,
4 See also,
Use with computers:
In web browsers, default settings typically distinguish hyperlinks by underlining them (and usually changing their color), but both users and websites can change these settings to make some or all hyperlinks appear differently (or even without distinction from normal text).
HTML and CSS:
The HTML special inline element