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, and IE 8 - IE 11. A list of supported commands can be found 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/0.7.1/katex.min.css" integrity="sha384-wITovz90syo1dJWVh32uuETPVEtGigN07tkttEqPv+uR2SE/mbQcG7ATL28aI9H0" crossorigin="anonymous">
<script src="https://cdnjs.cloudflare.com/ajax/libs/KaTeX/0.7.1/katex.min.js" integrity="sha384-/y1Nn9+QQAipbNQWU65krzJralCnuOasHncUFXGkdwntGeSvQicrYkiUBwsgUqc1" 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. If true 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. If false the math will be rendered in inline mode. (default: false)
• throwOnError: boolean. If true, KaTeX will throw a ParseError when it encounters an unsupported command. If false, KaTeX will render the unsupported command as text in the color given by errorColor. (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.

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.

Contributing

See CONTRIBUTING.md

License

KaTeX is licensed under the MIT License.