phantomjs 里面加了得ajax 同步为什么没效果

var webpage=require('webpage');
var url="http://segmentfault.com";
var page=webpage.create();

page.onLoadFinished = function(status){
    if(status==="success"){
        var result=page.evaluate(function(){
            var url="http://segmentfault.com/q/1010000004337401?_ea=575071";
            var result="";
            $.ajaxSetup({   async : false  });
            $.get(url,function(data){
                result=data;
            });
            return result;
        });

        console.log('result:%s',result);
        phantom.exit();
    }
};