Input Fields as part of MathJax - mathjax/MathJax-docs GitHub Wiki
From https://groups.google.com/d/msg/mathjax-users/ueAqvvR1F1g/doNggSQgJSoJ
Is it possible to insert an input field into a given equation display by mathjax so that the user can make an input there?
See the forminput extension in the repository of user-contributed extensions for something that may do what you want, but note that this may not work in all output modes.
Davide