title: JS function being called twice?
body: <p>I can't seem to find the bug that's making the code run twice, and JSFiddle isn't working for me so I can't double check if it's the editor.</p>
  
  <pre><code>var friends = {};
  friends.bill = {
      firstName: "Bill",
      lastName: "Gates",
      number: 9,
      address: ["5242", "drank avenue"]
  };
  friends.steve = {
      firstName: "Steve",
      lastName: "Jobs",
      number: 8,
      address: ["3368", "pool lane"]
  };
  
  var list = function(person)
  {
      for (var friendName in person)
          console.log(friendName);
  };
  
  list(friends);
  </code></pre>
  
  <hr>
  
  <pre><code>Output:
  bill
  steve
  bill
  steve
  </code></pre>