nodejs 返回json、jsonp

var http = require('http');
var urllib = require('url');

var port = 10011;
var data = {"dest_adcode": 110101, msg": "ok"};

http.createServer(function(req, res){  
  var params = urllib.parse(req.url, true);
  if (params.query && params.query.cb) {
    var str =  params.query.cb + '(' + JSON.stringify(data) + ')';//jsonp  
    res.end(str);  
  } else {  
    res.end(JSON.stringify(data));//普通的json  
  }       
}).listen(port, function(){  
  console.log('server is listening on port ' + port);    
})