scratch/output/Scratch/js/MathJax/docs/rst/output.rst

.. _output-formats:

**********************
MathJax Output Formats
**********************

Currently, MathJax can render math in two ways:

- Using HTML-with-CSS to lay out the mathematics, or
- Using a browser's native MathML support.

These are implemented by the `HTML-CSS` and `NativeMML` output
processors.  You select which one you want to use by including either
``"output/HTML-CSS"`` or ``"output/NativeMML"`` in the `jax` array of
your MathJax configuration.  For example

.. code-block:: javascript

    jax: ["input/TeX","output/HTML-CSS"]

would specify TeX input and HTML-with-CSS output for the mathematics
in your document.

The HTML-CSS output processor produces high-quality output in all
major browsers, with results that are consistent across browsers and
operating systems.  This is MathJax's primary output mode.  It's major
advantage is its quality and consistency; it's drawback is that it is
slower that the NativeMML mode at rendering the mathematics.  (The
HTML-CSS processor has not yet been optimized for speed, so you can
expect some improvement in the future.  Note that IE8 in "IE8
standards mode" is an order of magnitude slower than any other browser
when processing math through the HTML-CSS output processor; see
:ref:`HTML-CSS with IE8 <html-css-with-ie8>` below for some strategies
to deal with this.)

The NativeMML output processor uses the browser's internal MathML support (if
any) to render the mathematics.  Currently, Firefox has native support
for MathML, and IE has the `MathPlayer plugin
<http://www.dessci.com/en/products/mathplayer/>`_ for rendering
MathML.  Opera has some built-in support for MathML that works well
with simple equations, but fails with more complex formulas, so we
don't recommend using the NativeMML output processor with Opera.  Safari,
Chrome, Konqueror, and most other browsers don't support MathML
natively.

The advantage of the NativeMML output Processor is its speed, since
native MathML support is much faster than using complicated HTML and
CSS to lay out mathematics via an interpreted language like JavaScript
(as the HTML-CSS output processor does).  The disadvantage is that you
are dependent on the browser's MathML implementation for your
rendering, and these vary in quality of output and completeness of
implementation.  MathJax may rely on features that are not available
in some renderers (for example, Firefox's MathML support does not
implement some of the named widths, such as
``negativethinmathspace``).  The results using the NativeMML output
processor may have spacing or other rendering problems that are
outside of MathJax's control.

Automatic Selection of the Output Processor
===========================================

Since not all browsers support MathML natively, it would be unwise to
choose the NativeMML output processor unless you are sure of your
audience's browser capabilities.  MathJax can help with that, however,
since there is a special configuration file that will choose between
NativeMML and HTML-CSS depending on the browser in use.  To invoke it,
add ``"MMLorHTML.js"`` to your configurations `config` array, and **do
not** include an output processor in your `jax` array; MathJax will
fill that in for you based on the abilities of your user's browser.

.. code-block:: javascript

   config: ["MMLorHTML.js"],
   jax: ["input/TeX"]

You can customize which choice to make on a browser-by-browser basis
or a global basis.  See the ``config/MathJax.js`` file or the
:ref:`Configuring MathJax <configuration>` section for futher
details.

MathJax produces MathML that models the underlying mathematics as best
it can, rather than using complicated hacks to improve output for a
particular MathML implementation.  When you make the choice to use the
NativeMML output processor, you are making a trade-off: gaining speed
at the expense of quality and reliability, a decision that should not
be taken lightly.  Note, however, that a user can employ the MathJax
contectual menu to select the other other renderer if he or she
wishes.


.. _html-css-with-ie8:

HTML-CSS with IE8
=================

Internet Explorer 8 has at least eight different rendering modes in
which can operate, and that are triggered by the `DOCTYPE` of the
document being viewed.  It's "quirks" mode is its fasted mode, and its
"IE8 standards" mode is its slowest.  This is the mode triggered by
strict HTML document types, and since most modern content management
systems now include a `DOCTYPE` that activates "standards" mode, IE8
will operate in its slowest manner.  This is particularly apparent
when MathJax is used, since IE8 in standards mode runs 20 to 30 times
slower than its does in its IE7 emulation mode, and 60 times slower
than in quirks mode.

Most users find this speed reduction unacceptable when there is much
mathematics on the page.  To overcome this problem, you may wish to
tell IE8 to use its IE7 emulation mode rather than its IE8 standards
mode.  You can accomplish this by including the line

.. code-block:: html

    <meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7">

at the top of the ``<head>`` section of your HTML documents.  This
lets you keep the strict `DOCTYPE` for validation purposes, while
still managing to get reasonable perforance from Internext Explorer
8.  Note that this line must come at the beginning of the ``<head>``,
before any stylesheets or other content are loaded.

Altertnatively, you can use the `MMLorHTML` configuration file
described above to select NativeMML output when possible, and request
that your users install the `MathPlayer plugin
<http://www.dessci.com/en/products/mathplayer/>`_, which will render
the mathematics much more quickly.