You load MathJax into a web page by including its main JavaScript file into the page. That is done via a <script> tag that links to the MathJax.js file. To do that, place the following line in the <head> section of your document:

<script type="text/javascript" src="path-to-MathJax/MathJax.js"></script>


where path-to-MathJax is replaced by the URL of the copy of MathJax that you are loading. For example, if you are using the MathJax distributed network service, the tag might be

<script type="text/javascript"
src="http://cdn.mathjax.org/mathjax/latest/MathJax.js">
</script>


If you have installed MathJax yourself, path-to-MathJax will be the location of MathJax on your server, or (if you are using MathJax locally rather than through a server) the location of that directory on your hard disk. For example, if the MathJax directory is at the top level of your web server’s directory hierarchy, you might use

<script type="text/javascript" src="/MathJax/MathJax.js"></script>


If you install MathJax on a server in a domain that is different from the one containing the page that will load MathJax, then there are issues involved in doing so that you need to take into consideration. See the Notes About Shared Servers for more details.

When you load MathJax, it is common to request a specific configuration file as discussed in the section on Using a Configuration File below, and in more detail in the Common Configurations section. A typical invocation of MathJax would be

<script type="text/javascript"
src="http://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML">
</script>


which loads MathJax with a configuration file that includes everything you need in order to enter mathematics in either TeX, LaTeX, or MathML notation, and produces output using MathML if the browser supports that well enough, or HTML-with-CSS otherwise. If you don’t load an explicit configuration file, you will need to include an in-line configuration block in order to tell MathJax how to read and display the mathematics on your pages. See the section below on Using In-line Configuration Options for details.

It is best to load MathJax in the document’s <head> block, but it is also possible to load MathJax into the <body> section, if needed. If you do this, load it as early as possible, as MathJax will begin to load its components as soon as it is included in the page, and that will help speed up the processing of the mathematics on your page. MathJax does expect there to be a <head> section to the document, however, so be sure there is one if you are loading MathJax in the <body>.

It is also possible to load MathJax dynamically after the page has been prepared, for example, via a GreaseMonkey script, or using a specially prepared bookmarklet. This is an advanced topic, however; see Loading MathJax Dynamically for more details.

MathJax is available as a web service from cdn.mathjax.org, so you can obtain MathJax from there without needing to install it on your own server. The CDN is part of a distributed “cloud” network, so it is handled by servers around the world. That means that you should get access to a server geographically near you, for a fast, reliable connection.

The CDN hosts the most current version of MathJax, as well as older versions, so you can either link to a version that stays up-to-date as MathJax is improved, or you can stay with one of the release versions so that your pages always use the same version of MathJax.

The URL that you use to obtain MathJax determines the version that you get. The CDN has the following directory structure:

mathjax/         # project-name
1.0-latest/
1.1-latest/   # the 1.1 release with any critical patches
2.0-latest/   # the 2.0 release with any critical patches
2.1-latest/   # the 2.1 release with any critical patches
2.2-latest/   # the 2.2 release with any critical patches
2.3-latest/   # the 2.3 release with any critical patches
2.4-latest/   # the 2.4 release with any critical patches
2.5-latest/   # the 2.5 release with any critical patches
...
latest/       # the most current version (2.5-latest in this case)


Each directory corresponds to an official MathJax release; however, hotfixes (urgent bug fixes) will be applied in each release branch as necessary, even if new releases are not prepared. In other words, 1.1-latest will initially point to v1.1, but over time may be updated with patches that would correspond to releases that might be numbers 1.1a, 1.1b, etc., even if such releases are not actually packaged for separate distribution (they likely won’t be). We may occasionally introduce directories for betas, as indicated above, but they will be temporary, and will be removed after the official release.

To load from a particular release, use the directory for that release. For example,

<script type="text/javascript" src="http://cdn.mathjax.org/mathjax/2.0-latest/MathJax.js"></script>


loads the v2.0 version, even after v2.1 or later versions are released, while

<script type="text/javascript" src="http://cdn.mathjax.org/mathjax/latest/MathJax.js"></script>


will always be the most current stable release, so it will go from v2.3 to the next version automatically when that is released. Note that all the versions available on the CDN are stable versions; the development version is not hosted on the CDN. (If you wish to use the development version of MathJax, you will need to install your own copy; see Installing and Testing MathJax for information on how to do that.)

The use of cdn.mathjax.org is governed by its terms of service, so be sure to read that before linking to the MathJax CDN server.

If you wish to use the MathJax CDN but use your own configuration file rather than one of the pre-defined ones, see the information at the end of the Using a Local Configuration File section below.

## Configuring MathJax¶

There are two ways to configure MathJax: via a configuration file, or by including configuration commands within the web page itself. These can be used independently, or in combination. For example, you can load a main pre-defined configuration file, but include in-line commands to adjust the configuration to your needs.

Note that you must use at least one of these two forms of configuration. Unlike MathJax v1.0, version 1.1 and higher does not load a default configuration file. If you have been using version 1.0’s config/MathJax.js for your configuration, you will need to load that configuration file explicitly via a config parameter, as described below.

## Using a configuration file¶

The first way to configure MathJax is to use a configuration file. MathJax comes with a number of pre-defined configuration files, which are stored in the MathJax/config directory. Among these are the following

default.js

A file that contains nearly all the configuration options with comments describing them, which you can edit to suit your needs.

TeX-AMS-MML_HTMLorMML.js

Allows math to be specified in TeX, LaTeX, or MathML notation, with the AMSmath and AMSsymbols packages included, producing output using MathML if the browser supports it sufficiently, and HTML-with-CSS otherwise.

TeX-AMS_HTML.js

Allows math to be specified in TeX or LaTeX notation, with the AMSmath and AMSsymbols packages included, and produces output using the HTML-CSS output processor.

MML_HTMLorMML.js

Allows math to be specified using MathML notation, and produces MathML output if the browser supports it sufficiently, or HTML-CSS output otherwise.

AM_HTMLorMML.js

Allows math to be specified using AsciiMath notation, producing output in MathML if the browser supports it sufficiently, or as HTML-with-CSS otherwise.

TeX-AMS-MML_SVG.js

Allows math to be specified in TeX, LaTeX, or MathML notation, with the AMSmath and AMSsymbols packages included, producing output using SVG.

TeX-MML-AM_HTMLorMML.js

Allows math to be specified in TeX, LaTeX, MathML, or AsciiMath notation, with the AMSmath and AMSsymbols packages included, producing output using MathML if the browser supports it sufficiently, and HTML-with-CSS otherwise.

The first of these is a file that you can edit to suit your needs. It contains nearly all the configuration options that MathJax allows, and has comments explaining them. The others are what are called combined configuration files, which not only configure MathJax, but also pre-load the various files that the configuration requires. (The contents of these files are explained in more detail in the Common Configurations section.)

Usually, MathJax loads its components only when they are needed, but each component will require a separate file to be loaded, and that can cause delays before the mathematics is displayed. The combined configuration files load the majority of the needed files all as one large file, reducing the number of network requests that are needed. That means you will probably be getting the components that MathJax needs faster than you would without the combined file, but you may be loading components that are never actually used; that is the trade off.

Each of the combined configuration files comes in two flavors: the ones listed above, which only configure the output processors but don’t include the main code, and a “full” version, that also includes the complete output processors. For example, with TeX-AMS_HTML.js and TeX-AMS_HTML-full.js, the latter includes the complete HTML-CSS output processor. The “full” configuration files are substantially larger (on the order of 70KB more), so you need to decide whether it is worth loading the full configuration for your pages.

To load a configuration file, use config=filename (where filename is one of the names above without the .js) as a parameter to the URL of the MathJax.js file. For example

<script type="text/javascript"
src="http://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML">
</script>


loads the config/TeX-AMS-MML_HTMLorMML.js configuration file from the MathJax distributed network service.

You can include more than one configuration file by separating them with commas. For example, if you have a locally defined configuration file called MathJax/config/local/local.js that modifies the settings for the TeX-AMS_HML configuration, defines some new TeX macros, and so on, you can use

<script type="text/javascript"
src="path-to-MathJax/MathJax.js?config=TeX-AMS_HTML,local/local">
</script>


to first load the main configuration, then the local modifications.

## Using a local configuration file with the CDN¶

You can load MathJax from the MathJax CDN server but still use a configuration from your own local server. For example, suppose you have a configuration file called local.js on your own server, in a directory called MathJax/config/local. Then you can load MathJax from the CDN and still use your configuration file as follows:

<script type="text/javascript"
src="http://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS_HTML,http://myserver.com/MathJax/config/local/local.js">
</script>


Because the local.js file is not on the CDN server, you must give the complete URL to the local configuration file. Note that you also have to edit the loadComplete() call that is at the bottom of the configuration file to change it from [MathJax]/config/local/local.js to the complete URL as you give it in the config parameter. In the example above, it would be

MathJax.Ajax.loadComplete("http://myserver.com/MathJax/config/local/local.js");


That is because the [MathJax] in the original URL refers to the root directory where MathJax.js was loaded, which is on the CDN, not your local server, and so you need to tell MathJax the actual location of your configuration file.

## Using in-line configuration options¶

The second way to configure MathJax is through in-line configuration, which puts the configuration options within the web page itself. The use of in-line configuration with MathJax requires two separate <script> tags: one for specifying the configuration settings and one for loading of MathJax. Because MathJax starts its configuration process as soon as it is loaded, the configuration script must come before the script tag that loads MathJax.js itself. You do this by including a <script> with type="text/x-mathjax-config" whose content will be run when MathJax performs its configuration. Generally, this script will include a MathJax.Hub.Config() call to perform MathJax configuration, but it can also include other MathJax commands, such as registering signal actions, or any JavaScript commands that you want. You can have as many such script tags as you need, and MathJax will process them in the order in which they appear in the document.

For instance,

<script type="text/x-mathjax-config">
MathJax.Hub.Config({
extensions: ["tex2jax.js"],
jax: ["input/TeX", "output/HTML-CSS"],
tex2jax: {
inlineMath: [ ['$','$'], ["\$$","\$$"] ],
displayMath: [ ['$$','$$'], ["\$","\$"] ],
processEscapes: true
},
"HTML-CSS": { availableFonts: ["TeX"] }
});
</script>
<script type="text/javascript" src="path-to-MathJax/MathJax.js">
</script>


This example includes the tex2jax preprocessor and configures it to use both the standard TeX and LaTeX math delimiters. It uses the TeX input processor and the HTML-CSS output processor, and forces the HTML-CSS processor to use the TeX fonts rather than other locally installed fonts (e.g., STIX fonts). See the configuration options section (or the comments in the config/default.js file) for more information about the configuration options that you can include in the MathJax.Hub.Config() call. This configuration does not load any pre-defined configuration file.

Note that you can combine in-line configuration with file-based configuration; simply include text/x-mathjax-config scripts as above, but also include config=filename when you load the MathJax.js file. For example, the tex2jax preprocessor does not enable the TeX single-dollar in-line math delimiters by default. You can load one of the pre-defined configuration files that includes the TeX preprocessor, and use an in-line configuration block to enable the single-dollar signs, as in this example:

<script type="text/x-mathjax-config">
MathJax.Hub.Config({
tex2jax: {
inlineMath: [ ['$','$'], ["\$$","\$$"] ],
processEscapes: true
}
});
</script>
<script type="text/javascript" src="path-to-MathJax/MathJax.js?config=TeX-AMS_HTML">
</script>


## Using plain JavaScript¶

Starting with MathJax version 2.3, it is possible to set window.MathJax to a configuration object in any JavaScript code before MathJax’s startup. MathJax will then use that object for its initial configuration. For instance the previous example becomes:

<script type="text/javascript">
window.MathJax = {
tex2jax: {
inlineMath: [ ['$','$'], ["\$$","\$$"] ],
processEscapes: true
}
};
</script>
<script type="text/javascript" src="path-to-MathJax/MathJax.js?config=TeX-AMS_HTML">
</script>


Similarly to scripts with the custom type text/x-mathjax-config, you can enter arbitrary code to execute during the configuration phase. You just need to put that code in an AuthorInit function:

<script type="text/javascript">
window.MathJax = {
AuthorInit: function () {
... initialization code ...
}
};
</script>


Note that this initialization code runs before the MathJax.Hub.queue is set up, so if you want to queue additional actions during the AuthorInit function, use

<script type="text/javascript">
window.MathJax = {
AuthorInit: function () {
MathJax.Hub.Register.StartupHook("Begin",function () {
MathJax.Hub.Queue(
)
});
}
};
</script>


## Configuring MathJax after it is loaded¶

Because MathJax begins its configuration process immediately after it is loaded (so that it can start loading files as quickly as it can), the configuration blocks for MathJax must come before MathJax.js is loaded, so they will be available to MathJax when it starts up. There are situations, however, when you might want to put off configuring MathJax until later in the page.

One such situation is when you have a site that loads MathJax as part of a theme or template, but want to be able to modify the configuration on specific pages of the site. To accomplish this, you need to ask MathJax to delay its startup configuration until some later time. MathJax uses the delayStartupUntil parameter to control the timing of the startup sequence. By default, it is set to none, meaning there is no delay and MathJax starts configuration right away.

You can set delayStartupUntil=onload in order to prevent MathJax from continuing its startup process until the page’s onLoad handler fires. This allows MathJax to find the text/x-mathjax-config blocks that occur anywhere on the page, not just the ones that appear above the <script> that loads MathJax.js. It also means that MathJax will not begin loading any of the files that it needs until then as well, which may delay the displaying of your mathematics, since the onLoad handler doesn’t execute until all the images and other media are available. (If you have used a combined configuration file, however, it already includes all the main files that MathJax needs, so there is not much loss in delaying the startup.)

You can set delayStartupUntil=configured in order to delay the startup configuration until the MathJax.Hub.Configured() method is called. This allows you to delay startup until later on the page, but then restart the MathJax configuration process as soon as possible rather than waiting for the entire page to load. For example, you could use

<script type="text/javascript"
src="path-to-MathJax/MathJax.js?config=TeX-AMS-MML_HTMLorMML&delayStartupUntil=configured">
</script>


<script type="text/javascript">
MathJax.Hub.Configured()
</script>


in its footer, so that MathJax will delay setting up until the footer is reached, but will not have to wait until images and other files are loaded. In this way, if you have text/x-mathjax-config script tags within the main body of the document, MathJax will read and process those before continuing its startup. In this way you can use a default configuration that can be modified on a page-by-page basis.

Note that MathJax.Hub.Configured() is not called by MathJax; you must make that call somewhere within the page yourself after the configuration blocks are set up. If you do not execute this function, MathJax will not process any of the math on the page.

## Details of the MathJax configuration process¶

Since there are a number of different ways to configure MathJax, it is important to know how they interact. The configuration actions are the following:

1. Execute AuthorInit() from in-line MathJax = {...}.
2. Process any configuration file explicitly specified as a script parameter via config=.
3. Perform author configuration from in-line MathJax = {...}
4. Process the in-line script body (deprecated), if present.
5. If delayed startup is requested, wait for the indicated signal.
6. Process text/x-mathjax-config config blocks.
7. Process any config files queued in the configuration’s config array by earlier config code.

Note that text/x-mathjax-config script blocks must either precede the MathJax.js script element, or you must request a delayed startup. Otherwise, blocks that follow the MathJax.js script element may or may not be available when MathJax runs, and browser-dependent erratic behavior will result. Similarly, window.MathJax must be created before MathJax.js is loaded. If you set the MathJax variable afterward, you will disable MathJax entirely!