When looping over arrays, it is recommended to use:
```js
   for (var i = 0, l = array.length; i < l ; i++) {
      /* ... */
   }
```
rather than
```js
   for (var i in array) {
      /* ... */
   }
```
because it is quicker, the order of iteration is guaranteed and you don't need to add a check for ``hasOwnProperty``.