在一個項目上想用NodeJS，所以邊學(xué)邊練。第一個遇到的問題就是跨域訪問控制問題。很多初學(xué)者會遇到同樣問題。

問題

在前端的JS（http://localhost/xxx）中ajax訪問后端RestAPI(http://localhost:3000/….)時(Chrome)報錯：

XMLHttpRequest cannot load http://localhost:3000/auth/xxx/xxx. Origin http://localhost is not allowed by Access-Control-Allow-Origin.

方案

解決代碼如下：

var express = require('express');
var app = express();
//設(shè)置跨域訪問
app.all('*', function(req, res, next) {
    res.header("Access-Control-Allow-Origin", "*");
    res.header("Access-Control-Allow-Headers", "X-Requested-With");
    res.header("Access-Control-Allow-Methods","PUT,POST,GET,DELETE,OPTIONS");
    res.header("X-Powered-By",' 3.2.1')
    res.header("Content-Type", "application/json;charset=utf-8");
    next();
});

app.get('/auth/:id/:password', function(req, res) {
    res.send({id:req.params.id, name: req.params.password});
});

app.listen(3000);
console.log('Listening on port 3000...');