# What’s New in MathJax v2.0

MathJax version 2.0 includes many new and improved features, including
much better speeds in Internet Explorer, a new AsciiMath input
processor, a new output processor, support for additional
LaTeX commands, and many bug fixes, to name just a few of the changes.

## Major speed improvement for HTML-CSS output, particularly in IE

The HTML-CSS output processing was redesigned to avoid the page
reflows that were the main source of the speed problem in Internet
Explorer 8 and 9. For test pages having between 20 and 50 typeset
expressions, we see an 80% reduction in output processing time for
IE8, a 50% reduction for IE9, and between 15% and 25% reduction for
most other browsers over the corresponding v1.1a times. Since the
processing time in v1.1a grows non-linearly in IE, you should see even
larger savings for pages with more equations when using v2.0. Forcing
IE7 emulation mode is no longer necessary (and indeed is no longer
recommended).

## Reduced flickering during typsetting

In the past, each expression was displayed as soon as it was typeset,
which caused a lot of visual flickering as MathJax processed the page.
In v2.0, the output is processed in blocks so that typeset expressions
are revealed in groups. This reduces the visual distraction, and also
speeds up the processing. The number of equations in a block can be
controlled through the EqnChunk parameter in the HTML-CSS or SVG
block of your configuration. See the configuration options for
HTML-CSS
and pages for details.

If the page URL includes a hash reference (a link to a particular
after the page has finished typsetting. (Since the size of the page
may have changed due to the mathematical typsetting, that location may
no longer be visible on screen, so MathJax moves there when it is done
with the initial typesetting.) You can control this behavior with the
positionToHash parameter in the main section of your
configuration. See the page for details.

## Automatic equation numbering of TeX formulas

The TeX input jax now can be configured to add equation numbers
(though the default is not to number equations so that existing pages
will not change their appearance). This is controlled through the
equationNumbers section of the TeX block of your configuration
(see the section for
details). You can request that the numbering follow the AMS-style
numbering of environments, or you can request that every displayed
equation be numbered. There are now \label, \ref, and
\eqref commands to make it easier to link to particular equations
within the document.

## Automatic line breaking of long displayed equations

MathJax now implements the MathML3 specification for automatic line
breaking of displayed equations in its HTML-CSS output. This is
disabled by default, but can be enabled via the linebreaks section
of the HTML-CSS or SVG block of your configuration (see the
section for
details). Note that automatic line breaking only applies to displayed
equations, not in-line equations, unless they are themselves longer
than a line. The algorithm uses the nesting depth, the type of
operator, the size of spaces, and other factors to decide on the
breakpoints, but it does not know the meaning of the mathematics, and
may not choose the optimal breakpoints. We will continue to work on
the algorithm as we gain information from its actual use in the field.

## New AsciiMath input jax and SVG output jax

MathJax currently processes math in either and
format, or notation; version 2.0 augments
that to include notation (see the ASCIIMathML

for details on this format). This is a notation that is easier for
students to use than TeX, and has been requested by the user
community. See the page
for details.

In addition to the HTML-CSS and Native MathML output available in
v1.1, MathJax v2.0 includes an -based output jax. This should
prove to be more reliable than the HTML-CSS output, as it avoids some
CSS, web-font, and printing issues that the HTML-CSS output suffers
from, and it currently has no browser-dependent code. The SVG mode
even works in some ebook readers (like Apple iBooks and Calibre). See
the documentation for details.

## New combined configuration files

Pre-defined configuration files that include the AsciiMath and SVG
processors are now available with MathJax v2.0. These include
AM_HTMLorMML, TeX-AMS-MML_SVG, and TeX-MML-AM_HTMLorMML.
See the section for details.

## MathJax contextual menu now available on mobile devices

that are based on the WebKit (Safari) and Gecko (Firefox) engines.
For Mobile Firefox, the menu is accessed by a tap-and-hold on any
expression rendered by MathJax (this is Mobile Firefox’s standard
method of triggering a contextual menu). In Mobile Safari, use a
double-tap-and-hold (you may need to zoom in a bit to be able to
accomplish this). This is the first step toward providing a better
interface for mobile devices.

## Improved support for screen readers

Some issues surrounding the use of screen readers and their
interaction with MathPlayer have been resolved in MathJax v2.0. In
control over some aspects of MathJax’s interface that were interfering
with some screen readers’ ability to properly identify the
mathematics. Several stability issues with MathPlayer have also been
addressed. In Internet Explorer when MathPlayer is installed, there
is now a new contextual menu item to allow you to specify what events
are handled by MathJax and what should be handled by MathPlayer. This
gives you finer control over MathPlayer’s interaction with some screen

## Many new TeX additions and enhancements

• New mhchem chemistry extension (adds \ce, \cf, and \cee macros)
• New cancel extension (adds \cancel, \bcancel, \xcancel, and \cancelto macros)
• New extpfeil extension (adds more stretchy arrows)
• New color extension (makes \color work as a switch, as in LaTeX).
Adds \definecolor, other color models, LaTeX named colors,
\colorbox, \fcolorbox, etc.
• New begingroup extension to allow macro definitions to be
localized. Adds \begingroup and \endgroup for isolating macro
declarations, and defines \let, \renewenvironment, \global, and
\gdef.
\toggle{math1}{math2}...\endtoggle macros.
• New \mmToken{type}[attributes]{text} macro for producing <mo>,
<mi>, <mtext>, and other token MathML elements directly.
• New \bbox[color;attributes]{math} macro to add background color,
• New \middle macro for stretchy delimiters between \left and \right.
• New \label, \ref, and \eqref macros for numbered equations.
• Better implementation of \not so it produces proper MathML when possible.
• Better implementation of \dots that selects \ldots or \cdots
depending on the context.
• Better implementation of \cases that automatically uses \text on
the second entry in each row.
extensions directory.
• Allow \newcomand to provide a default parameter.
• Allow \\ to take an optional argument that specifies additional
space between lines.
• Allow \\ to be used anywhere (to force a line break), not just in
arrays.
• Allow optional alignment parameter for array, aligned, and gathered
environments.

See the page for details on these
extensions and macros.

## Font enhancements

• Work around for the OS X Lion STIX font problem.
• Support for STIX-1.1 fonts (detection of which version you have,
and use data appropriate for that).
• New WOFF versions of the web fonts (smaller, so faster to
• Data for more stretchy characters in HTML-CSS output.
• Add support for Unicode planes 1 through 10 (not just the Math
Alphabet block) in HTML-CSS output.
• Increased timeout for web fonts (since it was switching to image
fonts too often, especially for mobile devices).
• Only switch to image fonts if the first web font fails to load (if
we can access one, assume we can access them all).
• Allow <mtext> elements to use the page font rather than MathJax
fonts (optionally). This is controlled by the mtextFontInerhit
configuration parameter for HTML-CSS and SVG output jax.
• Provide better control over the font used for characters that are
not in the MathJax fonts.
• Allow Firefox to use web-based fonts when a local URL uses MathJax
from the CDN (in the past it would force image fonts when that was
not necessary).

## Interface improvements

• The MathJax contextual menu has been reorganized to make it easier
to get the source view, and to control the parameters for
MathPlayer in IE.
• The MathJax contextual menu is available in mobile devices (see
description above).
• Warning messages are issued if you switch renderers to one that is
• MathJax now starts processing the page on the DOMContentLoaded
event rather than the page onload event (this allows the
mathematics to appear sooner).
• Native MathML output is now scaled to better match the surrounding
font (like it is for HTML-CSS output).
• Better CSS styling for NativeMML output in Firefox in order to
handle \cal and other fonts.
• MathML output now (optionally) includes class names to help mark
special situations generated by the TeX input jax. (This lets the
MathML from the Show Source menu item better reproduce the original
TeX output.)
• MathJax now loads the menu and zoom code (if they haven’t been
they will be available immediately when a user needs those
features, but do not delay the initial typesetting of the
mathematics.
• For the tex2jax preprocessor, the processClass can now be
used to override the skipTags to force a tag that is usually
skipped to have its contents be processed.
• The noErrors and noUndefined extensions can now be disabled via
a configuration option (since they are included in many of the
combined configuration files). See the noErrors and
• There is a new MathJax.Hub.setRenderer() function that can
be used to switch the current renderer. See the MathJax Hub
API
documentation for details.
• A user-defined macros is no longer overridden if an extension is
• Improved web-font detection reliability.

## Important changes from previous versions

• The default renderer for Firefox has been changed from NativeMML to
HTML-CSS (in those configurations that choose between the two).
The only browser that defaults to NativeMML is now IE with
MathPlayer installed. You can configure this to your liking using
the .

• NativeMML output will now be selected in IE9 when MathPlayer is
present (since IE9 was released the same day as MathJax v1.1a, and
there had been problems with IE9 beta releases, we weren’t sure if
MathPlayer would work with the official release, and so did not
select NativeMML by default.)

• The performance improvements in IE8 and IE9 now make it unnecessary
to use a <meta> tag to force IE7 emulation mode. In fact IE9 in
IE9 standards mode now runs faster than IE9 in IE7 standards mode,
and IE8 in IE8 standards mode is comparable to IE8 in IE7 standards
mode. We now recommend that you use

<meta http-equiv="X-UA-Compatible" content="IE=edge">

to obtain the highest emulation mode available in IE, which
will be the fastest one for MathJax 2.0.

• The tex2jax preprocessor now balances braces when looking for the
closing math delimiter. That allows expressions like

$y = x^2 \hbox{ when$x > 2$}$

to be properly parsed as a single math expression rather than two
separate ones with unbalanced braces. The old behavior can be
obtained by setting balanceBraces to false in the tex2jax
block of your configuration. (See the tex2jax configuration
options
for details.)

• If you are hosting your own copy of MathJax on your server, and
that copy is being used from pages in a different domain, you will
have set up the access control paramters for the font directory to
allow Firefox to access the font files properly. Since MathJax 2.0
includes fonts in WOFF format, you will need to include woff in
you access control declaration for the fonts. E.g., use

<FilesMatch "\.(ttf|otf|eot|woff)\$">
</IfModule>
</FilesMatch>

in the .htaccess file for the `Mathjax/fonts directory if you
are using the Apache web server. See Notes about shared
installations
for details.

• The \cases macro now properly places the second column in text
mode not math mode. In the past, one needed to use \text in
the second column to achieve the proper results; pages that did
this will still work properly in v2.0. Pages that took advantage
of the math mode in the second column will need to be adjusted.

• The \dots macro now produces \ldots or \cdots depending
on the context (in the past, \dots always produced \ldots).

• A one pixel padding has been added above and below HTML-CSS and SVG
output so that math on successive lines of a paragraph won’t bump
into each other.

• There is a new MathPlayer submenu of the Math Settings menu in
the MathJax contextual menu that allows the user to control what
events are passed on to MathPlayer. This allows better control for
events are being passed on to MathPlayer, the MathJax menu can be
obtained by ALT-clicking on a typeset expression (so the user can
still access MathJax’s other features).

• In order to improve stability with IE when MathPlayer is installed,
MathJax now adds the namespace and object bindings that are needed
for MathPlayer at the time that Mathjax is first loaded, rather
than waiting for the NativeMML output jax to be loaded. Since
this is before the configuration information has been obtained,
this will happen regardless of whether the NativeMML output jax
is requested. This means that IE may ask the user to allow
MathPlayer to be used, and may show the MathPlayer splash dialog
even when MathPlayer is not in the end used by MathJax. Note that
this setup can only be performed if MathJax is loaded explicitly as
part of the initial web page; if it is injected into the page later
by adding a <script> tag to the page dynamically, then
MathPlayer will be set up when the NativeMML jax is loaded as in
the past, and some stability issues may occur if events are passed
to MathPlayer.

• The MathJax typesetting is now started on DOMContentLoaded
rather than at the page onload event, when possible, so that
means MathJax may start typesetting the page earlier than in the
past. This should speed up typesetting one pages with lots of
images or side-bar content, for example.

• MathJax now attempts to determine whether the page’s onload
event had already occurred, and if it has, it does not try to wait
initial typeset pass. This means that it is no longer necessary to
call MathJax.Hub.Startup.onload() by hand if you insert MathJax
into the page dynamically (e.g., from a GreaseMonkey script).

• If the page URL includes a hash reference (a link to a particular
after the page has finished typsetting. Since the size of the page
may have changed due to the mathematical typsetting, that location
may no longer be visible on screen, so MathJax moves there when it
is done with the initial typesetting. You can control this
behavior with the positionToHash parameter in the main section

• In the event that MathJax is not able to load the configuration file
you have specified in the script tag that loads MathJax.js via
config=filename, it will no longer issue the warning message
about a missing configuration. The configuration process changed
in v1.1, and that message was to help page maintainers update their
configurations, but it turns out that for users with slow network
connections, MathJax could time out waiting for the configuration
file and would issue the warning message in that case, even though
the page included the proper configuration. That should no longer
occur in MathJax v2.0.

## Other enhancements

• Use prioritized lists of callbacks for StartupHooks, MessageHooks,
LoadHooks, PreProcessors, and pre- and post-filters on the input jax.
• Updated operator dictionary to correspond to current W3C version.
• Improved browser detection for Gecko and WebKit browsers.
• Make prefilters and postfilters for all input jax, and make them into
hook lists rather than a single hook.
• Use <mi> rather than <mo> for \sin, \cos, and other
such functions, for \mathop{\rm...} and \operatorname.
• Add &ApplyFunction; after \mathop{} and other macros that are
functions (e.g., \sin).
• The MathJax_Preview style has been moved from HTML-CSS/jax.js to
MathJax.js, since it is common to all output.
• The autobold extension now uses \boldsymbol rather than
\bf so that it will affect more characters.
• Make units of mu‘s be relative to the scriptlevel (as they
are supposed to be).
• Reorganized the event-handling code to make it more modular and reduce
redundancy in the different output jax.
• Modified CSS in NativeMML output for Firefox to use local copies of
the web fonts, if they are available.
• Error messages now have the MathJax contextual menu.
• Better handling of some characters not in the web fonts (remap to
locations where they exist, when possible).
• Better choice of accent characters in some cases.
• Better handling of pseudo-scripts (like primes).
• Better sizing of characters introduced by \unicode{}, or
otherwise outside of the fonts known to MathJax.
• Provide a new extension to handle tagged equations better in
HTML-CSS output when there are floating elements that might
reduce the area available to displayed equations. (See the
HTML-CSS extensions section of the documentation for detais.)
• Use a text font for \it rather than the math italics, so
spacing is better.
• Handle italic correction better in HTML-CSS output
• Handle href attributes better, especially when on [itex]
elements.
• Allow \sqrt\frac{}{} without producing an error.

## Other bug fixes

• MathPlayer setup changed to prevent crashes.
• Moved remapping of <mo> contents to the output jax so that the
original contents aren’t changed.
• Don’t combine mathvariant with fontstyle or fontweight
(as per the MathML specification).
• Isolate non-standard attributes on MathML elements so that they don’t
interfere with the inner workings of MathJax.
• Properly handle width of border and padding in merrors in HTML-CSS
output.
• Properly handle lower-case Greek better.
• Process weight and style of unknown characters properly.
• Fixed spacing problems with \cong in MathJax web fonts .
• Choose better sizes for \widehat and \widetilde
• Fixed problem with detecting em/ex sizes when uses in mobile devices
with small screen widths.
• Fixed MathML output when dimensions of mu‘s are used in TeX input.
• Better handling of table borders from TeX.
• Fixed some problems with table widths and heights, and spacing.
• Better handling of colored backgrounds in HTML-CSS output.
• Handle border and padding CSS styles better in HTML-CSS output.
• Fixed multline environment to put tags on bottom row when
TagSide is set to right.
• Force reflow after equations are typeset so that some rendering
problems in tables are corrected in Firefox and WebKit browsers.
• Fixed a number of bugs with the size of zoom boxes and the size of their
content.
• Have equations with tags zoom into a full-width zoom box to
accommodate the tag.
• Fixed positioning problem with zoom boxes in NativeMML mode.
• Don’t allow mouse events on zoomed math.
• Fixed MathJax.Hub.getJaxFor() and MathJax.Hub.isJax() to
properly handle elements that are part of an output jax’s output
(in particular, you can find the element jax from any DOM element
in the output).
• Fixed a number of font anomalies (problems in the data files).
• Fixed problem where <mspace> with a background color would not
always overlay previous items.
• Fixed a problem with colored <mspace> elements being too tall in
IE/quirks mode.
• Fixed problem where <mtable> with equalrows="true" would
not produce equal height rows.
• Allow <mpadded> background color to be specified exactly (i.e.,
without the 1px padding) when one of its dimensions is given
explicitly (or there is no content).
• Avoiding flicker problem with hover zoom trigger in Firefox.
• Fix \unicode bug with font names that include spaces.
• Remove internal multiple spaces in token elements as per the MathML
specification.
• Work around HTML5 removing namespaces, so that xmlns:xlink
becomes xlink with no namespace, which confuses the XML parsers.
• Fix MathJax.Message.Set() and MathJax.Message.Clear() so
that a delay of 0 is properly handled.
• Produce better MathML for \bmod, \mod, and \pmod.
• Don’t allow Safari/Windows to use STIX fonts since it can’t access
characters in Plane1 (the mathematical alphabets).
• Fix \thickapprox to use the correct glyph in HTML-CSS output
with MathJax web fonts.
• Make style attributes work on <mstyle> elements.
• Better handling of border and padding on MathML elements in
HTML-CSS output.
• Fixed error with size of \: space.
• Allow delimiter of . on \genfrac (it was accidentally rejected).
• Handle AMSmath control sequences with stars better (\cs{*} no longer
counts as \cs*).
• Fixed wrong character number in stretchy data for U+221A.
• Fixed <annotation-xml> to use the proper scaling in HTML-CSS
output.
• Fixed a problem with combining characters when they are used as
accents.
• Fixed a problem in Firefox with \mathchoice when the contents have
negative width.
• TeX input jax no longer incorrectly combines <mo> elements that have
different variants, styles, classes, or id’s.
• Fixed the scriptlevel when <munderover> has base with
movablelimits="true" in non-display mode.
• Fixed typo in implementation of SimpleSUPER.
• Fixed typo in self-closing flag for <mprescript> tag.
• Prevent infinite loop if one of the jax fails to load (due to failure
to compile or timeout waiting for it to load).
• Fixed a whitespace issue in token elements with IE/quirks mode in
the MathML input jax.
• Make sure height is above depth when making spaces and rules in
HTML-CSS and SVG output.
• Fixed HTML-CSS tooltip to be work properly when a restart occurs
within the tooltip.
• Fixed problem with size of colored backgrounds on <mo> in some
circumstances in HTML-CSS output.
• Make \ulcorner, etc. use more approprate unicode positions, and remap
those positions to the locations in the MathJax web fonts.

## Some technical changes

• Break the processing phase into two separate phases to do input
processing separately from output processing (they used to be
interleaved). This makes it easier to implement forward references
for the \ref macro.
• Make Font Preference menu honor the imageFont setting.
• Changed the name of the preview filter commands to previewFilter
in all preprocessors.
• Make ^ and _ be stretchy even though that isn’t in the W3C
dictionary.
• Fixed HTML-CSS output problem when a multi-character token element has
characters taken from multiple fonts.
• Force message text to be black in FontWarnings and configuration
warnings.
• Added signals for typesetting of unknown characters.
• Added More signals for error conditions.
• Allow preferences to select MathML output for Safari with late enough
version.
• Have tex2jax handle empty delimiter arrays and don’t scan page if
there is nothing to look for.
• Make delay following a processing message configurable and lengthen
it to make browser more responsive during typesetting.
• Make thin rules be in pixels to try to improve results in IE
(disappearing division lines).
• Mark all output elements as isMathJax, so it can be used to identify
what elements are part of mathematical output.
• Force MathZoom and MathMenu to wait for the Begin Styles message
before inserting their styles so when they are included in the
combined files, the author can still configure them.
• Add default id’s to the jax base object classes.
• Mark top-level math element as having a texError when it is one (to
make it easier to recognize).
• Have Update() method ask ElementJax to determine if it needs updating
(which in turn asks the associated input jax).
• Make Remove() work for just clearing output (without detaching) if
desired.
• Have ElementJax store input and output jax ID’s rather than pointers
(to help avoid circular references for cleanup purposes).
• Move input/output jax and preprocessor registries from Hub.config to
Hub itself (they are not user configurable through Hub.Config, and so
even though they are configurations, they don’t belong there).
• Make sure embelished large ops are type OP not ORD to get spacing
right.
• Added MathJax.HTML.getScript() to get the contents of a script (needed
since it works differently in different browsers).
• Move code that prevents numbers from being treated as a unit for
super- and subscripts to the super- and subscript routine in the
TeX input jax (prevents making changes to \text{},
\hbox{}, \href{}, etc.).
• Make mml2jax work better with IE namespaces (IE9 no longer seems to
list the xmlns entries on the <html> element).