Footer's contents seems don't work about node-phantom

[alexscheelmeyer]

Hmm, I dont think this would work regardless of callback method or not. Currently the "set" method is used for setting values and those values are serialized at the node end and sent across to phantomjs for actual setting. The problem is that the serialization will not work for an object that contains methods.

I think to support this, one would need a very special "papersize" method on the page object that knows to expect methods as some arguments and serialize them properly.

I dont think it is something that is high on the priority list for me right now. So if it is important to you, you could do a pull request.