Javascript - Use closures sparingly? 
<p>I'm watching <a href="http://www.youtube.com/watch?v=mHtdZgou0qU">http://www.youtube.com/watch?v=mHtdZgou0qU</a>, and at about 13:37 (hehe), he shows a slide of a list of things to avoid due to the addition of a new object onto the scope chain. </p>

<p>I understand what he's saying with <code>using</code> and <code>try-catch</code> statements, as well as accessing out-of-scope variables, but I don't understand why closures should be avoided. If the closure's local variables are going to be on the top of the scope chain, where's the performance loss?</p>
