How to GET JSON data from my API on localhost with jQuery.getJSON

I have simple API on Node.js with fake user data using

Faker.js

var express = require('express'),
    app = express(),
    faker = require('faker');

app.set('port', process.env.PORT || 3500);

var router = new express.Router();

router.get('/api/user', function(req, res) {
    res.json({
        name: faker.name.findName(),
        email: faker.internet.email(),
        address: faker.address.streetAddress(),
        bio: faker.lorem.sentence(),
        image: faker.image.avatar()
    });
});

app.use('/', router);

var server = app.listen(app.get('port'), function() {
    console.log('Server up: http://localhost:' + app.get('port'));
});

it looks like this:

but when I’m trying to get this data using jQuery:

<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
    <script type="text/javascript" src="https://reddit.fun/473116/bower_components/jquery/dist/jquery.js"></script>
</head>
<body>
    <script type="text/javascript">
        $.getJSON('http://localhost:3500/api/user').done(function(data) {
            console.log(data)
        })
    </script>
</body>
</html>

I get the following error in the console:

XMLHttpRequest cannot load

localhost:3500/api/user

. No
‘Access-Control-Allow-Origin’ header is present on the requested
resource. Origin ‘null’ is therefore not allowed access.

or with jQuery AJAX:

<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
    <script type="text/javascript" src="https://reddit.fun/473116/bower_components/jquery/dist/jquery.js"></script>
</head>
<body>
    <script type="text/javascript">
        $.ajax({
            url: "http://localhost:3500/api/user",
            jsonp: "callback",
            dataType: "jsonp",
            success: function(data) {
                console.log(data);
            }
        });
    </script>
</body>
</html>

Tell me please how to fix this problem and why it happens. How to get JSON data from my API ?

Edit:

The problem was that my API is on
http://localhost:3500
and HTML with GET Request on
http://localhost:8000
but

CORS

has not supported. I write answer for this question in which this problem is solved

stackoverflow.com/a/36526208/6135469