jsAJAXPOST

<!DOCTYPE html>
<html lang="en" id="html">
<head>
    <meta charset="UTF-8">
    <title>XHR</title>
    <style>
        html,
        body {
            display: flex;
            align-items: center;
            justify-content: center;
        }

        .container {
            display: flex;
            flex-direction: column;
            justify-content: center;
            align-content: center;
            align-items: center;
            margin-top: 30px;
            position: relative;
        }

        .mainDiv {
            display: flex;
            flex-direction: row;
        }

        table, tr, td {
            border: 1px solid black;
            border-collapse: collapse;
            padding: 5px;
        }

        table {
            width: 70%;
            margin: 10px;
        }
    </style>
</head>
<body>
    <div id="container" class="container">
        <input type="number" id="userId">
    </div>
    <script>
        'use strict'

        //function getUser()
        let url = 'https://jsonplaceholder.typicode.com/users';
        let method = 'POST';
        let newUser = { id: 2607, name: 'avr39-ripe', company: 'itstep' };

        let xhr = new XMLHttpRequest();

        xhr.open(method, url);
        xhr.setRequestHeader('Content-type','application/json; charset=utf-8')
        xhr.addEventListener('load', function () {
            if (this.status >= 400) {
                console.log(`HTTP ERROR CODE: ${this.status}!`);
            }
            else {
                console.log(this.responseText);
            }
        });

        xhr.send(JSON.stringify(newUser));
    </script>
</body>
</html>