title: for (var propertyName in object) vs for (propertyName in object)?
body: <p>Which one of those two methods for iterating over the property names of an object are preferable?</p>
  
  <pre><code>for (var propertyName in object) {
  
  }
  </code></pre>
  
  <p>vs.</p>
  
  <pre><code>for (propertyName in object) {
  
  }
  </code></pre>
  
  <p>I know in the second example, propertyName becomes a global variable, which is something to avoid, so I guess the first one would be better, right?</p>