在PhantomJS中加载JSONP数据

I stuck on the following case:

I use PhantomJS to parse webpage. Webpage contains JSONP data which loads from other website. I'll try the following script:

var data = {};

function cb(d) {
  data = d;
}

var aj = jQuery.ajax({
       url: "http://url-to-jsonp&callback=cb",
       dataType: 'jsonp',
       jsonpCallback: 'cb',
       jsonp: 'callback'
});

aj.done(function(res) { console.log(data); } );

I expext to see arguments of cb() function, but data array is empty. I think it happend because phantomjs close before data loaded. Any idea how to solve this?