//設置跨域訪問
app.all(‘*‘, function(req, res, next) {
    res.header("Access-Control-Allow-Origin", "*");
    res.header("Access-Control-Allow-Methods", "GET,HEAD,OPTIONS,POST,PUT");
    // res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept, Authorization");
    next();
});
 

如果需要支持cookie，就要加入

 res.header(‘Access-Control-Allow-Credentials‘, true);

//設置跨域訪問
app.all(‘*‘, function (req, res, next) {
    res.header(‘Access-Control-Allow-Origin‘, req.headers.origin || ‘*‘);
    // res.header(‘Access-Control-Allow-Headers‘, ‘Content-Type,Content-Length, Authorization,Origin,Accept,X-Requested-With‘
 
);
    res.header(‘Access-Control-Allow-Methods‘, ‘GET, POST, OPTIONS, PUT, PATCH, DELETE‘);
    res.header(‘Access-Control-Allow-Credentials‘, true);
    res.header(‘X-Powered-By‘, ‘ 3.2.1‘);
    res.header(‘Content-Type‘, ‘application/json;charset=utf-8‘);
    if (req.method === ‘OPTIONS‘) {
        res.sendStatus(
 
200);
    } else {
        next();
    }
});

http://www.ruanyifeng.com/blog/2016/04/cors.html

express 設置header解決跨域問題