look at the js file

var key_binding = { 65: n("gs"), 90: n("a"), 83: n("as"), 88: n("b"), 67: n("c", 1), 70: n("cs", 1), 86: n("d", 1), 71: n("ds", 1), 66: n("e", 1), 78: n("f", 1), 74: n("fs", 1), 77: n("g", 1), 75: n("gs", 1), 188: n("a", 1), 76: n("as", 1), 190: n("b", 1), 191: n("c", 2), 222: n("c#", 2),

		49: n("gs", 1),
		81: n("a", 1),
		50: n("as", 1),
		87: n("b", 1),
		69: n("c", 2),
		52: n("cs", 2),
		82: n("d", 2),
		53: n("ds", 2),
		84: n("e", 2),
		89: n("f", 2),
		55: n("fs", 2),
		85: n("g", 2),
		56: n("gs", 2),
		73: n("a", 2),
		57: n("as", 2),
		79: n("b", 2),
		80: n("c", 3),
		189: n("cs", 3),
		219: n("d", 3),
		187: n("ds", 3),
		221: n("e", 3)
	};

SHIFT and CTROL go UP and DOWN an octave respectively.