You will need to install a user script manager extension to install this script.
This version of the Dozenator does not replace decimal with dozenal. Instead, it creates side-by-side annotated dozenal and decimal representations of each numeric value. The intent is to make Dozens Online into a teaching device relating dozenal numbers to decimal, Rosetta Stone like.
It also converts times and times of day to Primel equivalents (hours/minutes become "trice time", fraction-of-a-second page load times are expressed in jiffs).