title: Pro JavaScript programmer interview questions (with answers)
body: <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>