I think it's reasonable that MathJax would never want to apply a
text-decoration like "underline" to mathematical content except possibly a
single symbol. But I think that border-bottom would make sense for a
<span> in text that contains math (so outside the domain where MathJax
operates).
I'm neutral on whether this might lead to a viable change in tex4ht.
In the cited MWE each of the two \underline commands generates in tex4ht
"<span class="underline"> and that (outside the scope of MathJax) is tied
to the text-decoration "underline". Instead for the span with math one can
change the class attribute from "underline" to, say, "uline", and for that
class use the CSS property border-bottom instead of text-decoration, e.g.,
span.uline {border-bottom: 0.2ex solid black;}
-- Bill
--
William F Hammond
Email: [email protected]
https://www.facebook.com/william.f.hammond
http://www.albany.edu/~hammond/
