Version 3 is now the current version of MathJax. This document is for version 1.

The Base Jax Class

The MathJax.InputJax, MathJax.OutputJax and MathJax.ElementJax classes are all subclasses of the base Jax class in MathJax. This is a private class that implements the methods common to all three other jax classes.

Unlike most MathJax.Object classes, calling the class object creates a subclass of the class, rather than an instance of the class. E.g.,

MathJax.InputJax.MyInputJax = MathJax.InputJax({
  id: "MyInputJax",
  version: "1.0",

creates MathJax.InputJax.MyInputJax as a subclass of MathJax.InputJax.

Class Properties


The name of the jax directory (usually "[MathJax]/jax"). Overridden in the subclass to be the specific directory for the class, e.g. "[MathJax]/jax/input".


The name of the extensions directory (usually "[MathJax]/extensions").

Instance Properties


The name of the jax.


The version number of the jax.


The directory for the jax (e.g., "[MathJax]/jax/input/TeX").

require: null

An array of files to load before the jax.js file calls the MathJax.Ajax.loadComplete() method.

config: {}

An object that contains the default configuration options for the jax. These can be modified by the author by including a configuration subsection for the specific jax in question.



This is the method that the MathJax.Hub calls when it needs the input or output jax to process the given math <script>. Its default action is to start loading the jax’s jax.js file, and redefine itself to simply return the callback for the load operation (so that further calls to it will cause the processing to wait for the callback). Once the jax.js file has loaded, this method is replaced by the jax’s Translate() method, so that subsequent calls to Process() will perform the appropriate translation.

  • script — reference to the DOM <script> object for
    the mathematics to be translated

an ElementJax object, or null


This is a stub for a routine that should be defined by the jax’s jax.js file when it is loaded. It should perform the translation action for the specific jax. For an input jax, it should return the ElementJax object that it created. The Translate() method is never called directly by MathJax; during the loadComplete() call, this function is copied to the Process() method, and is called via that name. The default Translate() method throws an error indicating that the Translate() method was not redefined. That way, if the jax.js file fails to load for some reason, you will receive an error trying to process mathematics with this jax.

  • script — reference to the DOM <script> object for
    the mathematics to be translated

an ElementJax object, or null


This method is overridden in the InputJax, OutputJax and ElementJax subclasses to handle the registration of those classes of jax.

  • mimetype — the MIME-type to be associated with the jax



Inserts the configuration block for this jax from the author’s configuration specification into the jax’s config property. If the configuration includes an Augment object, that is used to augment the jax (that is, the configuration can override the methods of the object, as well as the data). This is called automatically during the loading of the jax.js file.


This is a method that can be overridden in the subclasses to perform initialization at startup time (after the configuration has occurred).


This is called by the config.js and jax.js files when they are completely loaded and are ready to signal that fact to MathJax. For config.js, this simply calls the MathJax.Ajax.loadComplete() method for the config.js file. For jax.js, the actions performed here are the following:

  1. Post the “[name] Jax Config” message to the startup signal.
  2. Perform the jax’s Config() method.
  3. Post the “[name] Jax Require” message to the startup signal.
  4. Load the files from the jax’s require and config.extensions arrays.
  5. Post the “[name] Jax Startup” message to the startup signal.
  6. Perform the jax’s Startup() method.
  7. Post the “[name] Jax Ready” message to the startup signal.
  8. Perform the MathJax.Ajax.loadComplete() call for the jax.js file.

Note that the configuration process (the Config() call) can modify the require or config.extensions arrays to add more files that need to be loaded, and that the Startup() method isn’t called until those files are completely loaded.