# Loading and Configuring MathJax¶

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="https://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>
```

to load MathJax.

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="https://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.

## Loading MathJax from the CDN¶

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
2.6-latest/ # the 2.6 release with any critical patches
2.7-latest/ # the 2.7 release with any critical patches
...
latest/ # the most current version (2.6-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="https://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="https://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 easiest way to configure MathJax is to use a configuration file.
MathJax comes with a number of pre-defined and pre-combined configuration files,
which are stored in the `MathJax/config`

directory.
The contents of these
files are explained in more detail in the Common Configurations section.

### Considerations for using combined configuration files¶

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_CHTML.js`

and
`TeX-AMS_CHTML-full.js`

, the latter includes the complete CommonHTML 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.

If most of your pages include mathematics, then it is to your advantage to load the full version, but if you are including MathJax in a theme file for a blog or wiki that only includes mathematics occasionally, then perhaps it is better to use the standard configuration instead, in which case the output processors are only loaded when they are actually needed, saving the loading of 70KB for pages that don’t. Of course, if your server is configured to compress the files it sends, the difference between the two is considerably reduced. Furthermore, most browsers will cache the JavaScript they receive, so the download cost should only occur on the first page a user views, so it may be best to use the “full” version after all. Note, however, that older mobile devices sometimes have limits on the size of files that they cache, so they may be forced to download the configuration on every page. You need to keep these issues in mind as you decide on which configuration to use.

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="https://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_CHTML">
</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_CHTML,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="https://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(
... your actions here ...
)
});
}
};
</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>
```

in your theme’s header file, and

```
<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:

- Execute
`AuthorInit()`

from in-line`MathJax = {...}`

. - Process any configuration file explicitly specified as a script parameter via config=.
- Perform author configuration from in-line
`MathJax = {...}`

- Process the in-line script body (deprecated), if present.
- If delayed startup is requested, wait for the indicated signal.
- Process
`text/x-mathjax-config`

config blocks. - 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!