MathJax extension does not work

MathJax extension does not work

[Rudolf Adamkovič]

I would like to use the "\mathclap" command from the "mathtools" package in my Org document. In LaTeX, it works. For HTML, I visited the Org manual [1] where I saw the following example:

#+HTML_MATHJAX: cancel.js noErrors.js

with a comment "it loads the two MathJax extensions ‘cancel.js’ and ‘noErrors.js’ [132]." (As a side-note, the first link in [132] points to 404.) Thus, I put the following into my Org file

#+HTML_MATHJAX: mathtools.js

but it seems to do nothing; the exported HTML code not even contain the word "mathtools".

A file that demonstrates the problem:

#+LATEX_HEADER: \usepackage{mathtools}
#+HTML_MATHJAX: mathtools.js

\begin{equation*}
\begin{aligned}
\lim_{R\to0}F_1
=\lim_{R\to0}\frac{2PR}{P+R}
=\lim_{R\to0}\frac{2\cdot0\cdot{}R}{0+R}
=\lim_{R\to0}\frac{0}{R},
=\underbrace{\lim_{R\to0}\frac{0}{1}}_{\mathclap{\text{by L'Hôpital's Rule with $\frac{d}{dR}R=1$}}}
=\lim_{R\to0}0
=0.
\end{aligned}
\end{equation*}

Rudy

[1] https://orgmode.org/manual/Math-formatting-in-HTML-export.html

-- 
"Logic is a science of the necessary laws of thought, without which no employment of the understanding and the reason takes place." -- Immanuel Kant, 1785

Rudolf Adamkovič <salutis@me.com>
Studenohorská 25
84103 Bratislava
Slovakia

[he/him]

Re: MathJax extension does not work

[Daniel Fleischer]

Rudolf Adamkovič <salutis@me.com> writes:

> I would like to use the "\mathclap" command from the "mathtools" package in my Org document. In LaTeX, it works. For

Hi, there are 2 problems: first the mathtools.js library was introduced in
mathjax 3.2 but org provided version 2.7 as can be seen in the HTML

#+begin_src html
<script src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.0/MathJax.js?config=TeX-AMS_HTML"></script>
#+end_src

One can use the newer mathjax by replacing this with
#+begin_src html
<script type="text/javascript" id="MathJax-script" async
  src="https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js">
</script>
#+end_src

as seen in https://docs.mathjax.org/en/latest/web/start.html.

You can just change the "path" in 'org-html-mathjax-options'.


Secondly, mathtools is not autoloaded so you need to call it; for
example you can put it in org using "export" block. 

#+begin_src HTML
<script>
window.MathJax = {
  loader: {load: ['[tex]/mathtools']},
  tex: {packages: {'[+]': ['mathtools']}}
};
</script>
#+end_src

After that it worked.

Not sure why the "#+HTML_MATHJAX: mathtools.js" doesn't do anything.
Need further investigation. 

-- 

Daniel Fleischer

Re: MathJax extension does not work

[Daniel Fleischer]

Daniel Fleischer <danflscr@gmail.com> writes:

> Not sure why the "#+HTML_MATHJAX: mathtools.js" doesn't do anything.
> Need further investigation. 

After examining the function 'org-html--build-mathjax-config' in
'ox-html.el' and also looking at the default values of

- 'org-html-mathjax-options'
- 'org-html-mathjax-template'

I don't see any code that loads mathjax extensions; which means
the documentation in

https://orgmode.org/manual/Math-formatting-in-HTML-export.html

is not accurate. That's my understanding.

-- 

Daniel Fleischer

Re: MathJax extension does not work

[Rudolf Adamkovič]

Daniel Fleischer <danflscr@gmail.com> writes:

> […] the mathtools.js library was introduced in mathjax 3.2 but org provided version 2.7 […]
> You can just change the "path" in 'org-html-mathjax-options'.

I see. I tried the following and it worked:

(with-eval-after-load 'ox-html
  (add-to-list 'org-html-mathjax-options
               '(path "https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js")))

> Secondly, mathtools is not autoloaded so you need to call it; for
> example you can put it in org using "export" block.
>
> #+begin_src HTML

The "export" blocks did not work for me, but the following did:

(setq-default org-html-head "
  <script>
  window.MathJax = {
    loader: {load: ['[tex]/mathtools']},
    tex: {packages: {'[+]': ['mathtools']}}
  };
  </script>")

> After that it worked.
> Not sure why the "#+HTML_MATHJAX: mathtools.js" doesn't do anything.

All the above makes using MathJax extensions impractical. I would have to include HTML hacks in my Org documents or tie the documents to my Emacs configuration, if I understand everything. Neither sounds right, and thus I will avoid using "modern" MathJax until Org switches to it and HTML_MATHJAX actually works.

P.S. I wonder why Org uses MathJax 2.x when other popular tools, such as Pandoc, use the latest one.

Thank you for your help!

Rudy

-- 
"'Contrariwise,' continued Tweedledee, 'if it was so, it might be; and if it were so, it would be; but as it isn't, it ain't. That's logic.'" -- Lewis Carroll, Through the Looking Glass

Rudolf Adamkovič <salutis@me.com>
Studenohorská 25
84103 Bratislava
Slovakia

[he/him]