This program is written entirely in javascript, which means that once you have loaded the page you can continue using it offline. Because even the MIDI is written in javascript, the program only works with Firefox, as far as I can tell.
The program currently runs in two modes, focusing either transposition classes or transposition/inversion classes.
For example, while the transposition classes of the major and minor triads are different—being [047] and [037] respectively—the transposition/inversion class is the same—both being [037].
As you begin, things may be slow. Work until you can get your average time to about 5 secs, but always try to keep at least a 80-90% accuracy. If your accuracy is low, slow down and listen carefully.
The octave span affects the span between the pitches played, thus increasing the difficulty level.
Change the MIDI instrument as you please. I personally like the Rhodes Piano, and sometimes the Rock Organ.
Created by Jeremiah Goyette, 2012