node实现jsonp跨域

1. 搭建node server

//引入模块

var http=require("http");

var fs=require("fs");
var url = require('url');
var querystring = require('querystring');

//创建服务器
var server=http.createServer();
server.on("request",function(req,res){
   console.log(req.url.split('?')[1])
   var urlpath=url.parse(req.url).pathname;
   var qs = querystring.parse(req.url.split('?')[1]);//callback=result
   if(urlpath === '/jsonp'){
               res.writeHead(200,{'Content-Type':'application/json;charset=utf-8'});
               function isJson(obj){
                   return typeof(obj)=="object"&&Object.prototype.toString.call(obj).toLowerCase()=="[object ]"
               }
                fs.readFile("fs.json",function(err,data){
                    if(err){console.log(err)}
                    data=JSON.parse(data);//因为data是buffer要把他变成json
                    data=JSON.stringify(data)
                    var callback = qs.callback+'('+data+');'；//callback：test（{json}）
                  res.end(callback);//res.end参数为buffer或者string
                })
           }else{
               res.writeHead(200, {'Content-Type':'text/html;charset=utf-8'});
               res.end('Hell World ');
           }
});
server.listen("3000");
console.log("server running at localhost:3000");

前端代码：

<!DOCTYPE html>
<html lang="en">
<head>
   <meta charset="UTF-8">
   <title>jsonp</title>
</head>
<body>
   <div id="box">hahahaha</div>
   <button id="but">click it</button>

   <script>
       function test(data){
                         alert(data.name);
                       }
   </script>
   <script src="http://localhost:3000/jsonp?callback=test"></script>

</body>
</html>