Thank you BurrMan.

So with a few modest changes to the script, the ends are now tangent. (The interpcurve factory did the work.)
Also the closed curve, full profile is created.
The full profile can be revolved 360 degrees to show the solid.

Removed the bottom checkbox.
Recreated var bottom = false, for the top half of the profile, and sent the points to the interpcurve factory.
Set bottom to true, and sent the bottom points to the interpcurve factory, using --i as a countdown from (numpoints-2), down to and including 0.

I suppose an x axis revolve axis could be added, and a revolve checkbox...

Added new EggOvoid2.zip to the first post. Removed old EggOvoid.js and EggOvoid.htm.

Very happy,
- Brian