Reason for using `prototype` instead of `this`
<p>I am using Lightbox2</p>

<p><a href="https://github.com/lokesh/lightbox2/blob/master/js/lightbox.js" rel="nofollow">https://github.com/lokesh/lightbox2/blob/master/js/lightbox.js</a></p>

<p>And I don't understand why all the inner members of Lightbox are prototyped (<code>Lightbox.prototype.init</code>) and not simply members (<code>Lightbox.init</code>)?</p>

<p>If they are specific to each instance of lightbox wouldn't it be easier to use <code>this.init</code>?</p>
