$("button").click(function() {
      $.ajax({
         url: 'http://***.com:3000/login',
         data: {
            format: 'json',
            username: $('#username').val(),
            password: $('#password').val()
         },
         error: function() {
            console.log("error");
            alert('FAIL');
         },
         dataType: 'jsonp',
         success: function(data) {
            alert('OK');
            console.log("success");
         },
         type: 'GET'
      });


   })

res.status(200).send("OK");