Pro JavaScript programmer interview questions (with answers)
<p>What are good questions to determine if applicant is really a pro JavaScript (browser side) developer ?</p>

<p>Questions that can distinguish if someone is not an ad-hoc JavaScript programmer, but is really doing professional JavaScript development, object-oriented, reusable, and maintainable.</p>

<p><strong>Please provide answers</strong>, so an intermediate and ad-hoc JavaScript programmers can interview someone more experienced, coming up with answers to quite few of those advanced questions will elude me. <strong>Please avoid open questions</strong>.</p>

<p>Please keep <strong>one <em>interview question/answer</em> per <em>SO answer</em></strong> for better reading experience and easier interview preparation.</p>

<p>It's possible duplicate, but there only questions and no answers (mostly):</p>

<ul>
<li><a href="http://stackoverflow.com/questions/1069857/advanced-javascript-interview-questions">Advanced JavaScript Interview Questions</a> </li>
<li><a href="http://stackoverflow.com/questions/2119826/what-questions-should-every-good-javascript-developer-be-able-to-answer">What questions should every good JavaScript developer be able to answer?</a></li>
</ul>
