Correct syntax for setting object's property to return value of an object-function?
<p>I'm learning javascript and was going through an example here:
<a href="https://developer.mozilla.org/en/A_re-introduction_to_JavaScript" rel="nofollow">https://developer.mozilla.org/en/A_re-introduction_to_JavaScript</a></p>

<pre><code>function personFullName() {  
    return this.first + ' ' + this.last;  
}  
function personFullNameReversed() {  
    return this.last + ', ' + this.first;  
}  
function Person(first, last) {  
    this.first = first;  
    this.last = last;  
    this.fullName = personFullName;  
    this.fullNameReversed = personFullNameReversed;  
}  
var x = new Person('mickey', 'mouse');
document.write(x.fullName());
</code></pre>

<p>Why are the lines of code </p>

<pre><code>    this.fullName = personFullName;  
    this.fullNameReversed = personFullNameReversed;  
</code></pre>

<p>instead of </p>

<pre><code>    this.fullName = personFullName();  
    this.fullNameReversed = personFullNameReversed();  
</code></pre>

<p>I thought we're setting <code>this.fullName</code> based on the return value of <code>personFullName()</code></p>
