\underline - LaTeX underline command

\underline x

Renderer support

Package	MathJax	KaTeX	XeTeX
`base`	MathJax: Full	KaTeX: Full	XeTeX: Full
`textmacros`	MathJax: Full	KaTeX: Full	XeTeX: Full

Syntax#

\underlinem{a}math content

Argspec m — one mandatory argument. In base. Reading argspecs

\underlinem:T{a}text content

Argspec m:T — one mandatory argument. In textmacros. Reading argspecs

\underline{x}

\underline{a+b+c}

\text{\underline{min}}

textmacros

\text{\underline x}

textmacros

\text{\underline{ab}}

Package	Signature	Allowed mode	Notes
`base`	`m`	math	Used to place an underline under a mathematical symbol or expression in formulas.
`textmacros`	`m:T`	text	Used to underline a text fragment, including short words or grouped text in text-mode content.

TeXForm parses this entry as prefix syntax; the package determines its argument specification.

`base`
Input	Case	MathJax	KaTeX	XeTeX
`\underline{a}`	Positive · baseline	Pass	Pass	Pass
`\underline a`	Positive · bare[0]	Pass	Pass	Pass

`textmacros`
Input	Case	MathJax	KaTeX	XeTeX
`\underline{a}`	Positive · baseline	Pass	Pass	Pass
`\underline a`	Positive · bare[0]	Pass	Pass	Pass
`\underline{a^2}`	Negative · neg:T[0]	Fail	Fail	Fail