katex

What is katex?

KaTeX is a fast, easy-to-use JavaScript library for TeX math rendering on the web. It provides a way to display mathematical notation in web pages, supporting a wide range of TeX functions and symbols.

What are katex's main functionalities?

Render TeX to HTML

This feature allows you to convert TeX expressions into HTML. The `renderToString` method takes a TeX string and returns an HTML string that can be inserted into a web page.

const katex = require('katex');
const html = katex.renderToString('c = \pm\sqrt{a^2 + b^2}');
console.log(html);

Render TeX to DOM

This feature allows you to render TeX expressions directly into a DOM element. The `render` method takes a TeX string and a DOM element, and it updates the element's content with the rendered math.

const katex = require('katex');
const element = document.getElementById('math');
katex.render('E = mc^2', element);

Auto-render TeX in HTML

This feature automatically finds and renders all TeX expressions within a given DOM element. The `renderMathInElement` function scans the element for TeX expressions and replaces them with rendered math.

const katex = require('katex');
const renderMathInElement = require('katex/contrib/auto-render');
renderMathInElement(document.body);

Other packages similar to katex

mathjax

MathJax is another popular JavaScript library for displaying mathematical notation in web pages. It supports a wider range of input formats, including TeX, MathML, and AsciiMath. MathJax is known for its high-quality rendering and extensive configurability, but it is generally slower than KaTeX.

asciimath

AsciiMath is a simpler alternative to KaTeX and MathJax, designed for ease of use. It uses a more human-readable syntax compared to TeX. While it is easier to write and understand, it does not support as many advanced mathematical features as KaTeX or MathJax.

README

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 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="//cdnjs.cloudflare.com/ajax/libs/KaTeX/0.3.0/katex.min.css">
<script src="//cdnjs.cloudflare.com/ajax/libs/KaTeX/0.3.0/katex.min.js"></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)

For example:

katex.render("c = \\pm\\sqrt{a^2 + b^2}", element, { displayMode: true });

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.

Changelog

[v0.5.1] - 2015-09-01

Added

• Added the font changing functions \mathrm, \mathit, \mathbf, \mathbb, \mathcal, \mathfrak, \mathscr, \mathsf, \mathtt, \Bbb, \bold, and \frak.
• Added the \limits and \nolimits functions.
• Added a throwOnError option to allow generating red error text when rendering invalid commands instead of throwing errors, and a corresponding errorColor option to decide the color of invalid commands.
• Added support for | column delimiters in the array environment.
• Added \lVert and \rVert symbols.

Changed

• Allow \lvert, \rvert, \lVert, \rVert, \lgroup, \rgroup, \lmoustache, and \rmoustache in delimiters.

Fixed

• Fix the spacing of the \ulcorner, \urcorner, \llcorner, \lrcorner, \barwedge, \veebar, \circledcirc, \boxdot, \uparrow, \Uparrow, \downarrow, \Downarrow, \updownarrow, \Updownarrow, and \ldots symbols.