Hi Tom,

Let u = r, the radius, which ranges from 0 through 1.
Let v = theta, the angle, ranging from just over 0, to (just under) 2PI ~= 6.2831253.
I tried the script equations with ln, sin, cos, and atan, which mostly reproduced the surface, with some problems with poles v = 0 and v = 2PI.

Using your implicit equation with sin, sinh(x) and sinh(y),
it becomes tedious to enter the equations into the fxgraph3d lines, so I've run out of time...
Best to write the equations in notepad++, as a .js file, and copy them over...then the parenthesis at least can match.
I set u = r and v = theta, as above, which I am not sure is right, but...
set x = u*sin(v)
set y = u*cos(v)

note that sinh(x) = (exp(x) - exp(-x))/2

z = asin((exp(u*sin(v))- exp((-1)*u*sin(v)))/2 * (exp(u*cos(v)) - exp((-1)*u*cos(v)))/2)
Does not work :-(

- Brian