# MathJax AsciiMath Support¶

The support for AsciiMath in MathJax consists of two parts: the asciimath2jax preprocessor, and the AsciiMath input processor. The first of these looks for mathematics within your web page (indicated by delimiters like ...) and marks the mathematics for later processing by MathJax. The AsciiMath input processor is what converts the AsciiMath notation into MathJax’s internal format, where one of MathJax’s output processors then displays it in the web page.

The AsciiMath input jax actually includes a copy of Peter Jipsen’s ASCIIMathML.js file (see the AsciiMath home page for details), and is included by permission of the author. This means that the results of MathJax’s AsciiMath processing should be the same as using the actual ASCIIMathML.js package (at least as far as the MathML that it generates is concerned). Thanks go to David Lippman for writing the initial version of the AsciiMath preprocessor and input jax.

The asciimath2jax preprocessor can be configured to look for whatever markers you want to use for your math delimiters. See the asciimath2jax configuration options section for details on how to customize the action of asciimath2jax.

The AsciiMath input processor handles conversion of your mathematical notation into MathJax’s internal format (which is essentially MathML). The AsciiMath input processor has few configuration options (see the AsciiMath options section for details).

The AsciiMath input jax handles only the original ASCIIMathML notation (from ASCIIMathML v1.4.7), not the extened LaTeXMathML notation added in version 2.0 of ASCIIMathML, though the AsciiMath input jax does expose the tables that define the symbols that AsciiMath processes, and so it would be possible to extend them to include additional symbols. In general, it is probably better to use MathJax’s TeX input jax to handle LaTeX notation instead.

## AsciiMath delimiters¶

By default, the asciimath2jax preprocessor defines the back-tick () as the delimiters for mathematics in AsciiMath format. It does not define $...$ as math delimiters. That is because dollar signs appear too often in non-mathematical settings, which could cause some text to be treated as mathematics unexpectedly. For example, with single-dollar delimiters, ”... the cost is $2.50 for the first one, and$2.00 for each additional one ...” would cause the phrase “2.50 for the first one, and” to be treated as mathematics since it falls between dollar signs. For this reason, if you want to use single-dollars for AsciiMath notation, you must enable that explicitly in your configuration:

MathJax.Hub.Config({
asciimath2jax: {
delimiters: [['$','$'], ['','']]
}
});


Note that the dollar signs are frequently used as a delimiter for mathematics in the TeX format, and you can not enable the dollar-sign delimiter for both. It is probably best to leave dollar signs for TeX notation.

See the config/default.js file, or the asiimath2jax configuration options page, for additional configuration parameters that you can specify for the asciimath2jax preprocessor, which is the component of MathJax that identifies AsciiMath notation within the page.

## AsciiMath in HTML documents¶

The AsciiMath syntax is descibed in the ASCIIMathML syntax page.

Keep in mind that your mathematics is part of an HTML document, so you need to be aware of the special characters used by HTML as part of its markup. There cannot be HTML tags within the math delimiters (other than <BR>) as AsciiMath-formatted math does not include HTML tags. Also, since the mathematics is initially given as text on the page, you need to be careful that your mathematics doesn’t look like HTML tags to the browser (which parses the page before MathJax gets to see it). In particular, that means that you have to be careful about things like less-than and greater-than signs (< and >), and ampersands (&), which have special meaning to the browsers. For example,

... when x<y we have ...

will cause a problem, because the brower will think <y is the beginning of a tag named y (even though there is no such tag in HTML). When this happens, the browser will think the tag continues up to the next > in the document (typically the end of the next actual tag in the HTML file), and you may notice that you are missing part of the text of the document. In the example above, the “we have ...” will not be displayed because the browser thinks it is part of the tag starting at <y. This is one indication you can use to spot this problem; it is a common error and should be avoided.

Usually, it is sufficient to simply put spaces around these symbols to cause the browser to avoid them, so

... when x < y we have ...

should work. Alternatively, you can use the HTML entities &lt;, &gt; and &amp; to encode these characters so that the browser will not interpret them, but MathJax will. E.g.,

... when x &lt; y we have ...
`

Keep in mind that the browser interprets your text before MathJax does.