What do the parentheses mean when you're declaring/calling a property?
<p><strong>Example 1</strong>:</p>

<pre><code>function a(){
  return "ok";
}

function b(){
  this.c = a;
}

var d = new b();
alert(d.c()); // Result "ok".
</code></pre>

<p><strong>Example 2</strong>:</p>

<pre><code>function b(){
    this.c = a();
}

var d = new b();
alert(d.c); // Result "ok".
</code></pre>

<p>What do the parentheses mean in this case?</p>
