The example not working(return empty result)

Hello,
I just try the example:

```

x('http://google.com', 'title')(function(err, str) {
  if (err) return done(err);
  console.log('result : ' + str);
})
```

but i got empty result.
If i try to get the html, i got:
`"<head></head><body></body>"`
