KaTeX is a fast, easy-to-use JavaScript library for TeX math rendering on the web.
- Fast: KaTeX renders its math synchronously and doesn't need to reflow the page. See how it compares to a competitor in this speed test.
- Print quality: KaTeX’s layout is based on Donald Knuth’s TeX, the gold standard for math typesetting.
- Self contained: KaTeX has no dependencies and can easily be bundled with your website resources.
- Server side rendering: KaTeX produces the same output regardless of browser or environment, so you can pre-render expressions using Node.js and send them as plain HTML.
KaTeX supports all major browsers, including Chrome, Safari, Firefox, Opera, Edge, and IE 9 - IE 11. More information can be found on the list of supported commands and on the wiki.
Usage
You can download KaTeX and host it on your server or include the katex.min.js
and katex.min.css
files on your page directly from a CDN:
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/KaTeX/0.9.0-alpha2/katex.min.css" integrity="sha384-exe4Ak6B0EoJI0ogGxjJ8rn+RN3ftPnEQrGwX59KTCl5ybGzvHGKjhPKk/KC3abb" crossorigin="anonymous">
<script src="https://cdnjs.cloudflare.com/ajax/libs/KaTeX/0.9.0-alpha2/katex.min.js" integrity="sha384-OMvkZ24ANLwviZR2lVq8ujbE/bUO8IR1FdBrKLQBI14Gq5Xp/lksIccGkmKL8m+h" crossorigin="anonymous"></script>
In-browser rendering
Call katex.render
with a TeX expression and a DOM element to render into:
katex.render("c = \\pm\\sqrt{a^2 + b^2}", element);
If KaTeX can't parse the expression, it throws a katex.ParseError
error.
Server side rendering or rendering to a string
To generate HTML on the server or to generate an HTML string of the rendered math, you can use katex.renderToString
:
var html = katex.renderToString("c = \\pm\\sqrt{a^2 + b^2}");
// '<span class="katex">...</span>'
Make sure to include the CSS and font files, but there is no need to include the JavaScript. Like render
, renderToString
throws if it can't parse the expression.
Rendering options
You can provide an object of options as the last argument to katex.render
and katex.renderToString
. Available options are:
displayMode
:boolean
. Iftrue
the math will be rendered in display mode, which will put the math in display style (so\int
and\sum
are large, for example), and will center the math on the page on its own line. Iffalse
the math will be rendered in inline mode. (default:false
)throwOnError
:boolean
. Iftrue
, KaTeX will throw aParseError
when it encounters an unsupported command. Iffalse
, KaTeX will render the unsupported command as text in the color given byerrorColor
. (default:true
)errorColor
:string
. A color string given in the format"#XXX"
or"#XXXXXX"
. This option determines the color which unsupported commands are rendered in. (default:#cc0000
)macros
:object
. A collection of custom macros. Each macro is a property with a name like\name
(written"\\name"
in JavaScript) which maps to a string that describes the expansion of the macro. Single-character keys can also be included in which case the character will be redefined as the given macro (similar to TeX active characters).colorIsTextColor
:boolean
. Iftrue
,\color
will work like LaTeX's\textcolor
, and take two arguments (e.g.,\color{blue}{hello}
), which restores the old behavior of KaTeX (pre-0.8.0). Iffalse
(the default),\color
will work like LaTeX's\color
, and take one argument (e.g.,\color{blue}hello
). In both cases,\textcolor
works as in LaTeX (e.g.,\textcolor{blue}{hello}
).maxSize
:number
. If non-zero, all user-specified sizes, e.g. in\rule{500em}{500em}
, will be capped tomaxSize
ems. Otherwise, users can make elements and spaces arbitrarily large (the default behavior).
For example:
katex.render("c = \\pm\\sqrt{a^2 + b^2}\\in\\RR", element, {
displayMode: true,
macros: {
"\\RR": "\\mathbb{R}"
}
});
Automatic rendering of math on a page
Math on the page can be automatically rendered using the auto-render extension. See the Auto-render README for more information.
Font size and lengths
By default, KaTeX math is rendered in a 1.21× larger font than the surrounding context, which makes super- and subscripts easier to read. You can control this using CSS, for example:
.katex { font-size: 1.1em; }
KaTeX supports all TeX units, including absolute units like cm
and in
.
Absolute units are currently scaled relative to the default TeX font size of
10pt, so that \kern1cm
produces the same results as \kern2.845275em
.
As a result, relative and absolute units are both uniformly scaled relative
to LaTeX with a 10pt font; for example, the rectangle \rule{1cm}{1em}
has
the same aspect ratio in KaTeX as in LaTeX. However, because most browsers
default to a larger font size, this typically means that a 1cm kern in KaTeX
will appear larger than 1cm in browser units.
Common Issues
- Many Markdown preprocessors, such as the one that Jekyll and GitHub Pages use,
have a "smart quotes" feature. This changes
'
to’
which is an issue for math containing primes, e.g.f'
. This can be worked around by defining a single character macro which changes them back, e.g.{"’", "'"}
. - KaTeX follows LaTeX's rendering of
aligned
andmatrix
environments unlike MathJax. When displaying fractions one above another in these vertical layouts there may not be enough space between rows for people who are used to MathJax's rendering. The distance between rows can be adjusted by using\\[0.1em]
instead of the standard line separator distance. - KaTeX does not support the
align
environment because LaTeX doesn't supportalign
in math mode. Thealigned
environment offers the same functionality but in math mode, so use that instead or define a macro that mapsalign
toaligned
.
Libraries
Angular2+
- ng-katex Angular module to write beautiful math expressions with TeX syntax boosted by KaTeX library
Contributing
See CONTRIBUTING.md
License
KaTeX is licensed under the MIT License.