Continued Fraction Calculator

This wonderful continued fraction calculator used to be found at www.mas.ncl.ac.uk/~nmcw/js/cfrac.html but that seems now to be a 404. It seems to be to be by far both the simplest and the most effective of the handful of continued fraction calculators that were easy to find in a quick search at the time. So simple it works offline so I downloaded it. Since it seems to no longer be available at that wonderful wonderful site I make it available here privately for your complete entertainment and instruction. For those of you equally wondering, the lesson manual is https://crypto.stanford.edu/pdc/notes/contfrac/matrix.html and the grandfather's wisdom is https://perl.plover.com/yak/cftalk/INFO