[tex4ht] \def does not seem to work in mathjax mode.

[Nasser M. Abbasi]

The following MWE does not compile OK in mathjax mode.
It works in lualatex and in default mode and in SVG mode.

=============================
\documentclass[12pt]{article}

\usepackage{amsmath}
\begin{document}
\def\st{\sin\theta(t)}
\begin{align*}
\dot{\theta}(t)  &  = \st
\end{align*}
\end{document}
================================

Compiled using

make4ht foo.tex "htm,mathjax"

It gives

https://www.12000.org/tmp/1292018/screen_shot_2.png

The problem is in the use of \def\st{\sin\theta(t)}

The latex code might not be the best, but it works
in the other systems.

Workaround for mathjax is easy, change it to

========================
\begin{document}
\begin{align*}
\dot{\theta}(t)  &  = \sin\theta(t)
\end{align*}
\end{document}
=======================

is \def not supposed to work in mathjax mode?

Thanks
--Nasser