Edit in JSFiddle

function Sphere(radius) {
    this.radius = radius;
}

Sphere.prototype.pi = 3.14;

Sphere.prototype.volume = function() {
    return Math.pow(this.pi, 3) * 3/4 * this.radius;
};

var startTime = Date.now();

var balls = [];
for (var x = 0; x < 1000000; x++) {
    balls[x] = new Sphere(10);
}

var elapsedTime = Date.now() - startTime;

document.body.innerHTML += "<p>Time to create 1 million balls: " + elapsedTime + "ms</p>";