Need form to "remember" which boxes are ticked between ajax refreshes

I have a form that uses ajax to load some of the elements. If the database says a checkbox has been previously ticked then the box itself is unavailable in the form. Ajax continuously checks and updates the form accordingly. The problem I’m having is when I check an available box ajax unchecks it the next time it refreshes. I just need the form to “remember” which boxes I’ve checked after an ajax update. Does anyone know how to retain new form entries between ajax refreshes?

Perhaps by passing the form information to the server, and having the server return the required state of the checkboxes?