cors in express

// CORS (Cross-Origin Resource Sharing) headers to support Cross-site HTTP requests

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-Headers', 'Content-Type');
       next();
});

//Cors = Cross-origin resource sharing

var express = require('express');
var cors = require('cors');
var app = express();

app.use(cors());

var corsOptions = {
  origin: 'http://example.com',
  optionsSuccessStatus: 200 // some legacy browsers (IE11, various SmartTVs) choke on 204
}

app.listen(80, function () {
  console.log('CORS-enabled web server listening on port 80')
})