FormatMathJax

 \spadtype{FormatMathJax} provides a coercion from
 \spadtype{OutputForm} to a \LaTeX{} format in a variant that can be
 understood by MahtJax (https://www.mathjax.org).

 \spad{environmnt(env, x, sep)} returns a handler that typesets
 its arguments (without parentheses) in a \LaTeX{} environment
 with name \spad{env}. The string \spad{x} is put right after
 the start of the environment.
 The arguments are separated by the string \spad{sep}.

 setPrettySymbols(true) sets the internal state in such a way
 that a symbol of the for "\abc", i.e. starting with a
 backslash and only ASCII letters following it ([a-zA-Z]),
 will not replace the backslash, but rather hands the symbol
 as is for interpretation by MathJax.
 setPrettySymbols(false) switches this feature off.
 The return value is the state before it was set anew.