Advanced Router - DocumentFragment() not supported in Safari and Firefox?

I was having issues in Safari and Firefox when testing the Advanced Router. It wasn't firing the xhr but is was firing _showSpinner(). For some odd reason when I changed `new DocumentFragment()` to `document.createElement('div')` it works in all the browsers I tested.

I know that DocumentFragment has performance benefits so I attempted to do

```
if (new DocumentFragment()) {
this._view = new DocumentFragment();
}
else {
this._view = document.createElement('div');
}
```

This worked in Chrome but still didn't work in Safari or FF. It appears that [DocumentFragment is well supported](http://caniuse.com/#search=documentfragment) so I'm confused by the xhr won't fire in those browsers if DocumentFragment is being used. I've shown [here](https://github.com/derekshull/styleguide/blob/gh-pages/js/components.js#L116) where I've changed the code to work in the browsers. Anyone have a thought on why this occurs and possibly how to fix it?