部署ajax服务-支持jsonp

server端代码

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

//访问地址：http://127.0.0.1:4000/?callback=ccc&name=allen&age=18&_=1491380773607
http.createServer(function(req, res) {
  var arg = url.parse(req.url,true).query;  //{callback:'ccc',name:'allen',age:'18',_'1491380773607'}
  var callbackName = arg.callback;
  var responseData = {'code':'A00000','data':'akalaka'}; 
  var responseString = JSON.stringify(responseData);
  //ajax访问时，没它会报错
  res.setHeader("Access-Control-Allow-Origin", "*");
  if (callbackName) {  
    var jsonpResponse =  callbackName+'('+responseString+')';
    //jsonpResponse =  'alert(123)';    //直接返回，会出弹窗
    res.end(jsonpResponse);  
  } else {  
    res.end(responseString);  
  } 
  console.log(req.url);
}).listen(4000);

console.log("HTTP server is listening at port 4000.");