# jsMath Sample Page

This is a sample file showing you how to use jsMath to display mathematics in your web pages. Be sure you have followed the installation instructions before loading this file. Also, you may need to edit the jsMath/easy/load.js file to set the root URL for where jsMath can be found on your web site. The rest of this document gives examples of how to enter mathematics in your pages. Depending on the settings in jsMath/easy/load.js, not all of the mathematics below will be processed by jsMath. Experiment with the settings in that file to see how they work.

## Some mathematics using tex2math

The easiest way to enter mathematics is to use jsMath's tex2math plugin to identify the mathematics in your document by looking for \rm\TeX-like math delimiters. Here are some math equations using those markers. Some inline math: $\sqrt{1-x^2}$ or $$ax^2+bx+c$$, and some displayed math: $$\int {1\over x}\,dx = \ln(x)+C$$ and $\sum_{i=1}^n i = {n(n+1)\over 2}.$ Note that the first of these will not be processed unless you have enabled processSingleDollars in jsMath/easy/load.js, which is disabled by default. That is because a single dollar sign can appear in normal text (as in "That will cost from $3.50 to$5.00 to repair"), and you don't want jsMath to try to typeset the "3.50 to " as mathematics.

If you enable processSingleDollars, you might also want to enable fixEscapedDollars, so that it is possible to enter dollar signs by preceding them with a backslash. Here's one that you can use to see the results of these settings: \$(an escaped dollar) and$x+1$(not escaped). It is also possible to use your own custom delimiters for marking the mathematics within your pages. If you uncomment the customDelimiters array in jsMath/easy/load.js, then the following math will be typeset by jsMath: some inline math $\sin(2\pi x)$ and some display math [display]x={-b\pm \sqrt{b^2-4ac}\over 2a}.[/display] You may change the delimiters to nearly anything you want, but they can not look like HTML tags, since some browsers will eliminate unknown tags, and jsMath doesn't get to look for the custom delimiters until after the browser has interpreted the page. You can prevent the tex2math plugin from processing a portion of a page by enclosing it in a tag that is of CLASS="tex2math_ignore". Often, that tag will be a DIV or SPAN, but it can be anything. This paragraph is wrapped in a DIV tag with CLASS="tex2math_ignore", and so no math delimiters will be processed:$f\colon X\to Y$, $$x^2 \gt 5$$, $$1\over 1+x^2$$ and $\matrix{a& b\cr c& d}.$ Note that this includes the processing of escaped dollars (\$) and custom delimiters ($a \mapsto a^2$) as well. This makes it possible to produce examples of how to enter mathematics on your site, for instance.

JsMath will automatically ignore the text within PRE tags, so you can easily enter examples that way as well:

   $f\colon X\to Y$, $$x^2 \gt 5$$,
$$1\over 1+x^2$$ and $\matrix{a& b\cr c& d}.$


Note that since the < and > symbols are used to denote HTML tags, these can be hard to incorporate into your \rm\TeX code. Often, putting spaces around the < or > will make it work, but it is probably better to use \lt and \gt instead. Also note that the tex2math plugin does not allow any HTML tags to be within the math delimiters, with the exception of <BR>, which is ignored.

## Mathematics without tex2math

If you are not using tex2math, then you will need to enclose your mathematics within SPAN or DIV tags that are of CLASS="math". Use a SPAN for in-line math and a DIV for displayed math. For instance, P = (x_1,\ldots,x_n) and

A = \left\lgroup\matrix{a_{11}& \cdots& a_{1m}\cr \vdots& \ddots& \vdots\cr a_{n1}& \cdots& a_{nm}\cr}\right\rgroup.