# Migrating from MathJax v1.0 to v1.1¶

MathJax v1.1 fixes a number of bugs in v1.0, and improves support for new versions of browsers and mobile devices. It includes changes to increase its performance, and to make it more compliant with HTML5. It has more flexible configuration options, and the ability to load configuration files that combine multiple files into a single one to increase loading speed when MathJax starts up. Finally, MathJax.org now offers MathJax as a web service through a distributed “cloud” server.

This document describes the changes you may need to make to your MathJax configurations in order to take advantage of these improvements.

## Configuration Changes¶

The main changes that you will see as a page author are in the way that MathJax can be loaded and configured. If you have been using in-line configuration by putting a MathJax.Hub.Config() call in the body of the <script> tag that loads MathJax, then your site should work unchanged with version 1.1 of MathJax. You may wish to consider moving to the new HTML5-compliant method of configuring MathJax, however, which uses a separate <script> tag to specify the configuration. That tag should come before the one that loads Mathjax.js, and should have type="text/x-mathjax-config" rather than type="text/javascript". For example,

<script type="text/javascript" src="/MathJax/MathJax.js">
MathJax.Hub.Config({
jax: ["input/TeX","output/HTML-CSS"],
extensions: ["tex2jax.js"]
});
</script>

would become

<script type="text/x-mathjax-config">
MathJax.Hub.Config({
jax: ["input/TeX","output/HTML-CSS"],
extensions: ["tex2jax.js"]
});
</script>
<script type="text/javascript" src="/MathJax/MathJax.js"></script>

instead. This will make sure your pages pass HTML5 validation. Be sure that you put the configuration block before the script that loads MathJax. See Loading and Configuring MathJax for more details.

If your page simply loads MathJax.js and relies on config/MathJax.js, then you will need to modify your <script> tag in order to use MathJax v1.1. This is because MathJax no longer loads a default configuration file; you are required to explicity specify the configuration file if you use one. Furthermore, the name of the config/MathJax.js file was a source of confusion, so it has been renamed config/default.js instead. Thus, if you used

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

in the past, you should replace it with

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

instead. If you don’t do this, you will receive a warning message that directs you to a page that explains how to update your script tags to use the new configuration format.

## Combined Configurations¶

New with version 1.1 is the ability to combine several files into a single configuration file, and to load that via the same script that loads MathJax. This should make configuring MathJax easier, and also helps to speed up the initial loading of MathJax’s components, since only one file needs to be downloaded.

MathJax comes with four pre-built configurations, and our hope is that one of these will suit your needs. They are described in more detail in the Using a Configuration File section. To load one, add ?config=filename (where filename is the name of the configuration file without the .js) to the URL that loads MathJax.js. For example

<script type="text/javascript" src="/MathJax/MathJax.js">
MathJax.Hub.Config({
jax: ["input/TeX","output/HTML-CSS"],
extensions: ["tex2jax.js","AMSmath.js","AMSsymbols.js"]
});
</script>

could be replaced by the single line

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

In this way, you don’t have to include the in-line configuration, and all the needed files will be downloaded when MathJax starts up. For complete details about the contents of the combined configuration files, see the Common Configurations section.

If you want to use a pre-defined configuration file, but want to modify some of the configuration parameters, you can use both a text/x-mathjax-config block and a config=filename parameter in combination. For example,

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

would load the TeX-AMS_HTML configuration file, but would reconfigure the inline math delimiters to include $...$ in addition to $$...$$, and would set the processEscapes parameter to true.

The MathJax installation is fairly substantial (due to the large number of images needed for the image fonts), and so you may not want to (or be able to) store MathJax on your own server. Keeping MathJax up to date can also be a maintenance problem, and you might prefer to let others handle that for you. In either case, using the MathJax distributed network service may be the best way for you to obtain MathJax. That way you can be sure you are using an up-to-date version of MathJax, and that the server will be fast and reliable.

To use the MathJax CDN service, simply load MathJax as follows:

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

Of course, you can load any configuration file that you wish, or use a text/x=mathajx-config block to configure MathJax in-line. More details are available, if you need them.

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

## Change in default TeX delimiters¶

In addition to the fact that MathJax v1.1 no longer loads a default configuration file, there is a second configuration change that could affect your pages. The config/MathJax.js file properly configured the tex2jax preprocessor to use only $$...$$ and not $...$ for in-line math delimiters, but the tex2jax preprocessor itself incorrectly defaulted to including $...$ as in-line math delimiters. The result was that if you used in-line configuration to specify the tex2jax preprocessor, single-dollar delimiters were enabled by default, while if you used file-based configuration, they weren’t.

This inconsistency was an error, and the correct behavior was supposed to have the single-dollar delimiters disabled in both cases. This is now true in v1.1 of MathJax. This means that if you used in-line configuration to specify the tex2jax preprocessor, you will need to change your configuration to explicitly enable the single-dollar delimiters if you want to use them.

For example, if you had

<script type="text/javascript" src="/MathJax/MathJax.js">
MathJax.Hub.Config({
jax: ["input/TeX","output/HTML-CSS"],
extensions: ["tex2jax.js"]
});
</script>

and you want to use single-dollar delimiters for in-line math, then you should replace this with

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

The same technique can be used in conjunction with a combined configuration file. For example

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

will load the pre-defined TeX-AMS_HTML configuration, but will modify the settings to allow $...$ delimiters, and to process \\$ to produce dollar signs within the text of the page.

## New Distribution Location¶

Version 1.0 of MathJax was distributed through SourceForge, but the development of MathJax has switched to GitHub, which is now the primary location for MathJax source code and distributions. The SourceForge repository will no longer be actively maintained (and hasn’t been since November 2010), and so you will not be able to obtain updates through svn if you checked out MathJax from there.

You may be able to switch to using the MathJax CDN (see above) rather than hosting your own copy of MathJax, and avoid the problem of updates all together. If you must install your own copy, however, you should follow the instructions at Installing and Testing MathJax, using either git or svn as described to obtain your copy from GitHub. This will allow you to keep your copy of MathJax up to date as development continues.

We apologize for the inconvenience of having to switch distributions, but the git-to-svn bridge we tried to implement to keep both copies in synch turned out to be unreliable, and so the SourceForge disrtibution was retired in favor of the GitHub site.