# TeX Input Processor Options¶

The options below control the operation of the TeX input processor that is run when you include 'input/tex', 'input/tex-full', or 'input/tex-base' in the load array of the loader block of your MathJax configuration, or if you load a combined component that includes the TeX input jax. They are listed with their default values. To set any of these options, include a tex section in your MathJax global object.

## The Configuration Block¶

MathJax = {
tex: {
packages: ['base'],        // extensions to use
inlineMath: [              // start/end delimiter pairs for in-line math
['\$$', '\$$']
],
displayMath: [             // start/end delimiter pairs for display math
['$$', '$$'],
['\$', '\$']
],
processEscapes: true,      // use \$to produce a literal dollar sign processEnvironments: true, // process \begin{xxx}...\end{xxx} outside math mode processRefs: true, // process \ref{...} outside of math mode digits: /^(?:[0-9]+(?:\{,\}[0-9]{3})*(?:\.[0-9]*)?|\.[0-9]+)/, // pattern for recognizing numbers tags: 'none', // or 'ams' or 'all' tagSide: 'right', // side for \tag macros tagIndent: '0.8em', // amount to indent tags useLabelIds: true, // use label name rather than tag for ids multlineWidth: '85%', // width of multline environment maxMacros: 1000, // maximum number of macro substitutions per expression maxBuffer: 5 * 1024, // maximum size for the internal TeX string (5K) baseURL: // URL for use with links to tags (when there is a <base> tag in effect) (document.getElementsByTagName('base').length === 0) ? '' : String(document.location).replace(/#.*$/, ''))
}
};


Note that some extensions make additional options available. See the TeX Extension Options section below for details.

Note also that the default for processEscapes has changed from false in version 2 to true in version 3.

## Option Descriptions¶

packages: ['base']

This array lists the names of the packages that should be initialized by the TeX input processor. The input/tex and input/tex-full components automatically add to this list the packages that they load. If you explicitly load addition tex extensions, you should add them to this list. For example:

MathJax = {
tex: {
packages: {'[+]': ['enclose']}
}
};

inlineMath: [['$$','$$']]

This is an array of pairs of strings that are to be used as in-line math delimiters. The first in each pair is the initial delimiter and the second is the terminal delimiter. You can have as many pairs as you want. For example,

inlineMath: [ ['$','$'], ['\$$','\$$'] ]


would cause MathJax to look for $...$ and $$...$$ as delimiters for in-line mathematics. (Note that the single dollar signs are not enabled by default because they are used too frequently in normal text, so if you want to use them for math delimiters, you must specify them explicitly.)

Note that the delimiters can’t look like HTML tags (i.e., can’t include the less-than sign), as these would be turned into tags by the browser before MathJax has the chance to run. You can only include text, not tags, as your math delimiters.

displayMath: [ ['$$','$$'], ['$','$'] ]

This is an array of pairs of strings that are to be used as delimiters for displayed equations. The first in each pair is the initial delimiter and the second is the terminal delimiter. You can have as many pairs as you want.

Note that the delimiters can’t look like HTML tags (i.e., can’t include the less-than sign), as these would be turned into tags by the browser before MathJax has the chance to run. You can only include text, not tags, as your math delimiters.

processEscapes: false

When set to true, you may use \$ to represent a literal dollar sign, rather than using it as a math delimiter. When false, \$ will not be altered, and its dollar sign may be considered part of a math delimiter. Typically this is set to true if you enable the $...$ in-line delimiters, so you can type \$ and MathJax will convert it to a regular dollar sign in the rendered document. processRefs: true When set to true, MathJax will process \ref{...} outside of math mode. processEnvironments: true When true, tex2jax looks not only for the in-line and display math delimiters, but also for LaTeX environments (\begin{something}...\end{something}) and marks them for processing by MathJax. When false, LaTeX environments will not be processed outside of math mode. digits: /^(?:[0-9]+(?:{,}[0-9]{3})*(?:.[0-9]*)?|.[0-9]+)/ This gives a regular expression that is used to identify numbers during the parsing of your TeX expressions. By default, the decimal point is . and you can use {,} between every three digits before that. If you want to use {,} as the decimal indicator, use MathJax = { tex: { digits: /^(?:[0-9]+(?:\{,\}[0-9]*)?|\{,\}[0-9]+)/ } };  tags: 'none' This controls whether equations are numbered and how. By default it is set to 'none' to be compatible with earlier versions of MathJax where auto-numbering was not performed (so pages will not change their appearance). You can change this to 'ams' for equations numbered as the AMSmath package would do, or 'all' to get an equation number for every displayed equation. tagSide: 'right' This specifies the side on which \tag{} macros will place the tags, and on which automatic equation numbers will appear. Set it to 'left' to place the tags on the left-hand side. tagIndent: "0.8em" This is the amount of indentation (from the right or left) for the tags produced by the \tag{} macro or by automatic equation numbers. useLabelIds: true This controls whether element IDs for tags use the \label name or the equation number. When true, use the label, when false, use the equation number. multlineWidth: "85%" The width to use for the multline environment that is part of the ams extension. This width gives room for tags at either side of the equation, but if you are displaying mathematics in a small area or a thin column of text, you might need to change the value to leave sufficient margin for tags. maxMacros: 10000 Because a definition of the form \def\x{\x} \x would cause MathJax to loop infinitely, the maxMacros constant will limit the number of macro substitutions allowed in any expression processed by MathJax. maxBuffer: 5 * 1024 Because a definition of the form \def\x{\x aaa} \x would loop infinitely, and at the same time stack up lots of a’s in MathJax’s equation buffer, the maxBuffer constant is used to limit the size of the string being processed by MathJax. It is set to 5KB, which should be sufficient for any reasonable equation. baseURL: (document.getElementsByTagName('base').length === 0) ? '' : String(document.location).replace(/#.*$/, ''))

This is the base URL to use when creating links to tagged equations (via \ref{} or \eqref{}) when there is a <base> element in the document that would affect those links. You can set this value by hand if MathJax doesn’t produce the correct link.

The remaining options are described in the Options Common to All Input Processors section.

## Developer Options¶

In addition to the options listed above, low-level options intended for developers include the following:

FindTeX: null

The FindTeX object instance that will override the default one. This allows you to create a subclass of FindTeX and pass that to the TeX input jax. A null value means use the default FindTeX class and make a new instance of that.

## TeX Extension Options¶

Several of the TeX extensions make additional options available in the tex block of your MathJax configuration. These are described below. Note that the input/tex component, and the combined components that load the TeX input jax, include a number of these extensions automatically, so some these options will be available by default.

### ConfigMacros Options¶

The configMacros extension adds a macros option to the tex block that lets you pre-define macros.

macros: {}

This lists macros to define before the TeX input processor begins. These are name: value pairs where the name gives the name of the TeX macro to be defined, and value gives the replacement text for the macro. The value can be a simple replacement string, or an array of the form [value, n], where value is the replacement text and n is the number of parameters for the macro. The array can have a third entry: either a string that is the default value to give for an optional (bracketed) parameter when the macro is used, or an array consisting of template strings that are used to separate the various parameters. The first template must precede the first parameter, the second must precede the second, and so on until the final which must end the last parameter to the macro. See the examples below.

Note that since the value is a javascript string, backslashes in the replacement text must be doubled to prevent them from acting as javascript escape characters.

For example,

macros: {
RR: '{\\bf R}',                    // a simple string replacement
bold: ['\\boldsymbol{#1}',1] ,     // this macro has one parameter
ddx: ['\\frac{d#2}{d#1}', 2, 'x'], // this macro has an optional parameter that defaults to 'x'
abc: ['(#1)', 1, [null, '\\cba']]  // equivalent to \def\abc#1\cba{(#1)}
}


would ask the TeX processor to define four new macros: \RR, which produces a bold-face “R”, and \bold{...}, which takes one parameter and sets it in the bold-face font, \ddx, which has an optional (bracketed) parameter that defaults to x, so that \ddx{y} produces \frac{dy}{dx} while \ddx[t]{y} produces \frac{dy}{dt}, and \abc that is equivalent to \def\abc#1\cba{(#1)}.

### Require Options¶

The require extension defines the (non-standard) \require{} macro for loading TeX extensions. Adding it to the packages array defines a require sub-block of the tex configuration block with the following values:

MathJax = {
tex: {
require: {
allow: {
base: false,
'all-packages': false
},
defaultAllow: true
}
};

allow: {...}

This sub-object indicates which extensions can be loaded by \require. The keys are the package names, and the value is true to allow the extension to be loaded, and false to disallow it. If an extension is not in the list, the default value is given by defaultAllow, described below.

defaultAllow: true

This is the value used for any extensions that are requested, but are not in the allow object described above. If set to true, any extension not listed in allow will be allowed; if false, only the ones listed in allow (with value true) will be allowed.

The autoload extension creates macros that cause the packages that define them to be loaded automatically when they are first used. Adding it to the packages array defines an autoload sub-block to the tex configuration block. This block contains key: value pairs where the key is a TeX package name, and the value is an array of macros that cause that package to be loaded, or an array consisting of two arrays, the first giving names of macros and the second names of environments; the first time any of them are used, the extension will be loaded automatically.

The default autoload definitions are the following:

MathJax = {
tex: {
action: ['toggle', 'mathtip', 'texttip'],
amsCd: [[], ['CD']],
bbox: ['bbox'],
boldsymbol: ['boldsymbol'],
braket: ['bra', 'ket', 'braket', 'set', 'Bra', 'Ket', 'Braket', 'Set', 'ketbra', 'Ketbra'],
cancel: ['cancel', 'bcancel', 'xcancel', 'cancelto'],
color: ['color', 'definecolor', 'textcolor', 'colorbox', 'fcolorbox'],
enclose: ['enclose'],
'xlongequal', 'xtofrom', 'Newextarrow'],
html: ['href', 'class', 'style', 'cssId'],
mhchem: ['ce', 'pu'],
unicode: ['unicode'],
verb: ['verb']
}
}
};


To prevent an extension from autoloading, set its value to an empty array. E.g., to not autoload the color extension, use

MathJax = {
tex: {
color: []
}
}
};


If you define your own extensions, and they have a prefix other than [tex], then include that in the extension name. For instance,

MathJax = {
tex: {
'[extensions]/myExtension' : ['myMacro', 'myOtherMacro']
}
}
};


See the Loader Options section for details about how to define your own prefixes, like the [extensions] prefix used here.

### TagFormat Options¶

The tagFormat extension allows you to control the display and linking of equation tags and numbers. Adding this to the packages array adds a tagFormat sub-object to the tex configuration block with the following values:

tagFormat: {
number: (n: number) => n.toString(),
tag:    (tag: string) => '(' + tag + ')',
id:     (id: string) => 'mjx-eqn-' + id.replace(/\s/g, '_'),
url:    (id: string, base: string) => base + '#' + encodeURIComponent(id),
}

number: function (n) {return n.toString()}

A function that tells MathJax what tag to use for equation number n. This could be used to have the equations labeled by a sequence of symbols rather than numbers, or to use section and subsection numbers instead.

tag: function (n) {return '(' + n + ')'}

A function that tells MathJax how to format an equation number for displaying as a tag for an equation. This is what appears in the margin of a tagged or numbered equation.

id: function (n) {return 'mjx-eqn-' + n.replace(/\s/g, '_')}

A function that tells MathJax what ID to use as an anchor for the equation (so that it can be used in URL references).

url: function (id, base) {return base + '#' + encodeURIComponent(id)}

A function that takes an equation ID and base URL and returns the URL to link to it. The base value is taken from the baseURL value, so that links can be make within a page even if it has a <base> element that sets the base URL for the page to a different location.

### Color Options¶

The color extension defines the LaTeX-compatible \color macro. Adding it to the packages array defines a color sub-block of the tex configuration block with the following values:

MathJax = {
tex: {
color: {
borderWidth: '2px'
}
}
};

padding: '5px'

This gives the padding to use for color boxes with background colors.

borderWidth: '2px'

This gives the border width to use with framed color boxes produced by \fcolorbox.

### AmsCD Options¶

The amsCd extension defines the CD environment for commutative diagrams. Adding it to the packages array defines an amsCd sub-block of the tex configuration block with the following values:

MathJax = {
tex: {
amsCd: {
colspace: '5pt',
rowspace: '5pt',
harrowsize: '2.75em',
varrowsize: '1.75em',
hideHorizontalLabels: false
}
}
};

colspace: '5pt'

This gives the amount of space to use between columns in the commutative diagram.

rowspace: '5pt'

This gives the amount of space to use between rows in the commutative diagram.

harrowsize: '2.75em'

This gives the minimum size for horizontal arrows in the commutative diagram.

varrowsize: '1.75em'

This gives the minimum size for vertical arrows in the commutative diagram.

hideHorizontalLabels: false

This determines whether horizontal arrows with labels above or below will use \smash in order to hide the height of the labels. (Labels above or below horizontal arrows can cause excess space between rows, so setting this to true can improve the look of the diagram.)