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();  });

给每个请求添加如上请求头即可