Why doesn't .__proto__ = .prototype in this example?
<p>I understand that "<em><code>__proto__</code> is an internal property of an object, pointing to its prototype</em>" so in the following example I would think that <code>c2.prototype</code> would equal <code>c2.__proto__</code>. Why do they not have the same value?</p>

<pre><code>&lt;!DOCTYPE html&gt;
&lt;html&gt;
    &lt;head&gt;
        &lt;script type="text/javascript"&gt;
            window.onload = function() {
                var Circle = function(radius) {
                    this.radius = radius;
                    this.doubleRadius = function() {
                        return this.radius * 2;
                    }
                }

                var c1 = new Circle(4);

                Circle.prototype.area = function() {
                    return Math.PI*this.radius*this.radius;
                }

                var c2 = new Circle(5);

                console.log('--- first circle object, created before adding "area" method');
                console.log(c1.radius);
                console.log(c1.doubleRadius());
                console.log(c1.area());

                console.log('--- second circle object, created after adding "area" method');
                console.log(c2.radius);
                console.log(c2.doubleRadius());
                console.log(c2.area());

                console.log(c2.prototype); // undefined
                console.log(c2.__proto__); // Object { area=function() }

            }
        &lt;/script&gt;
    &lt;/head&gt;
&lt;body&gt;
&lt;/body&gt;
&lt;/html&gt;
</code></pre>
