title: JavaScript object detection: dot syntax versus 'in' keyword
body: <p>I have seen two ways of detecting whether a UA implements a specific JS property: <code>if(object.property)</code> and <code>if('property' in object)</code>.</p>
  
  <p>I would like to hear opinions on which is better, and most importantly, why. Is one unequivocally better than the other? Are there more than just these two ways to do object property detection? Please cover browser support, pitfalls, execution speed, and such like, rather than aesthetics.</p>
  
  <p><strong>Edit:</strong>  Readers are encouraged to run the tests at <a href="http://jsperf.com/object-detection/6" rel="noreferrer">jsperf.com/object-detection</a></p>