MathJax with Tooltips
MathJax does not support tooltips by default. This is a sample that allows even overlapping tooltips.
$$
\newcommand{\target}[2]{\class{mathjax-symbol mathjax-symbol-#1}{#2}}
$$
Posterior
Likelihood
Prior
Evidence
$$P$$
$$A$$
$$B$$
Normal Math:
$$P(A\mid B) = \frac{P(B\mid A)P(A)}{P(B)}$$
Math with Tooltip: (Mouse hover to see tooltip)
$$
\target{posterior}{P(A\mid B)}=
\frac{
\target{likelihood}{P(B\mid A)}\target{prior}{P(A)}
}{
\target{evidence}{P(B)}
}
$$
Math with Overlapped Tooltip: (Mouse hover to see tooltip)
$$
\target{posterior}{
\target{p}{P}(\target{a}{A}\target{bar}{\mid} \target{b}{B})
}
=
\frac{
\target{likelihood}{\target{p}{P}(\target{b}{B}\target{bar}{\mid} \target{a}{A})}\target{prior}{\target{p}{P}(\target{a}{A})}
}{
\target{evidence}{\target{p}{P}(\target{b}{B})}
}
$$