1. 程式人生 > >JSONP前後端實現原理

JSONP前後端實現原理

前端:

    //動態建立script標籤,並請求
    function addScriptTag(src){
        var script = document.createElement('script');
        script.setAttribute('type', 'text/javascript');
        script.src = src;
        document.body.appendChild(script);
    };
    //如:在onload後,跨域請求
    window.onload = function(){
        addScriptTag('http://127.0.0.1:8080/jsonp?callback=monkey');
    };
    //回撥的方法,且必須為全域性方法,不然會報錯
    function monkey(data){
        alert(JSON.stringify(data));
    };

後端(node環境):

//引入node核心模組http
var http = require('http');
//引入url模組解析url字串
var url = require('url');
//引入querystring模組處理query字串
var querystring = require('querystring');
//建立新的HTTP伺服器
var server = http.createServer();
//通過request事件來響應request請求
server.on('request',function(req, res){
    var urlPath = url.parse(req.url).pathname;
    var qs = querystring.parse(req.url.split('?')[1]);
    if(urlPath === '/jsonp' && qs.callback){
        res.writeHead(200,{'Content-Type':'application/json;charset=utf-8'});
        var data = {
            "name": "Monkey"
        };
        data = JSON.stringify(data);
        var callback = qs.callback+'('+data+');';
        res.end(callback);
    }
    else{
        res.writeHead(200, {'Content-Type':'text/html;charset=utf-8'});
        res.end('hello');
    }
});
//監聽8080埠
server.listen('3000');
//用於提示我們伺服器啟動成功
console.log('Server running!');