javascript random point on unit sphere
function randomSpherePoint(x0,y0,z0,radius){
var u = Math.random();
var v = Math.random();
var theta = 2 * Math.PI * u;
var phi = Math.acos(2 * v - 1);
var x = x0 + (radius * Math.sin(phi) * Math.cos(theta));
var y = y0 + (radius * Math.sin(phi) * Math.sin(theta));
var z = z0 + (radius * Math.cos(phi));
return [x,y,z];
}