## Tuesday, December 22, 2009

### jsLaTeX: A jQuery plugin to directly embed LaTeX into your website or blog

jsLaTeX is the latest plugin I developed for jQuery and I wrote it so that I could easily be able to embed LaTeX directly into my blog but anyone can use it for their site.

You can download the normal, unpacked version for development or the packed version for production.

Here is a link to the jQuery plugin page, where you can find all the releases.

#### Usage Instructions

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js"></script>
<script src="jquery.jslatex.js"></script>


2. The simplest way to invoke the script is by calling the plugin with no parameters:

<script>
$(function () {$(".latex").latex();
});
</script>

<div class="latex">
\int_{0}^{\pi}\frac{x^{4}\left(1-x\right)^{4}}{1+x^{2}}dx =\frac{22}{7}-\pi
</div>


The above will render the following:

\int_{0}^{\pi}\frac{x^{4}\left(1-x\right)^{4}}{1+x^{2}}dx =\frac{22}{7}-\pi

The plugin works by taking the inner HTML of the specified container obviously assuming that it is valid LaTeX, and displays the image using CodeCogs LaTeX engine. The rendered output replaces the equation inside the container.

The plugin also accepts 3 optional parameters:
• format
• url
• callback

[format]
The format parameter is used to specify the format of the returned output. There are currently 3 supported formats:
• gif
• png
• swf

[url]
The url parameter is used to change the engine of the LaTeX generator. Let's take an example with a different engine, and in this case I will be using SITMO's LaTeX engine.
The url SITMO's engine uses to render the output is as follows:

http://www.sitmo.com/gg/latex/latex2png.2.php?z=100&eq=equation

where equation is the the LaTeX equation you wish to render.

Now we must tell the plugin where to put the equation and we do this by using the {e} specifier. This is how it can be used:

$(".latex").latex({url: 'http://www.sitmo.com/gg/latex/latex2png.2.php?z=100&eq={e}'});  As you can see from the above example, we placed the {e} specifier where the equation should be and then the engine takes care of the rest. Here is an example of using the new engine to render the output: \int_{0}^{\pi}\frac{x^{4}\left(1-x\right)^{4}}{1+x^{2}}dx =\frac{22}{7}-\pi The plugin currently supports another specifier: {f} and this is used for those engines that allow you to specify a file-format output. The file-types that are currently supported are the ones mentioned in the [format] section. If we take the 'original' engine url, we can turn into a url with specifiers like such: http://latex.codecogs.com/{f}.latex?{e} Here are examples of Engines you can use (ready with specifiers): Engines http://latex.codecogs.com/{f}.latex?{e} http://www.sitmo.com/gg/latex/latex2png.2.php?z=100&eq={e} http://www.forkosh.dreamhost.com/mathtex.cgi?{e} http://chart.apis.google.com/chart?cht=tx&chl={e} [callback] The callback parameter allows you to pass a function that will be executed after the image has been retrieved. In your callback function, this will refer to the newly created element (as a jQuery object) that contains the rendered output. The following example will set a border around your rendered output. $(".latex").latex({
callback : function() {
this.css({ border: '1px solid black'});
}
});


With the above callback, we can now render the following:

\int_{0}^{\pi}\frac{x^{4}\left(1-x\right)^{4}}{1+x^{2}}dx =\frac{22}{7}-\pi