在引用路由之前写下如下代码:

app.use('*', function(req, res, next) {

res.header("Access-Control-Allow-Origin", "*");

res.header("Access-Control-Allow-Headers",'Content-Type,Content-Length, Authorization, Accept,X-Requested-With');

res.header("Access-Control-Allow-Methods","PUT,POST,GET,DELETE,OPTIONS");

res.header("X-Powered-By",'3.2.1')

next();

});

即可用ajax完成跨域访问.