\fbox - LaTeX text command

\fbox{a}

Renderer support

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

Syntax#

\fboxm:T{a}text content

Argspec m:T — one mandatory argument. Reading argspecs

\fbox{x $y$}

\raisebox{1ex}{\fbox{$x^2$}}

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

\boxed{...}approximate
\boxed provides a similar framed box specifically intended for math-mode contents, but typically ensures contents remain in display/text style as appropriate, and is part of amsmath rather than standard LaTeX.

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