post.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Sparky! Go Fetch!</title>
    <script>
        const options = {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json'
            },
            body: JSON.stringify({
                brand: 'Apple',
                model: 'iPhone Xs',
                color: 'Space Gray'
            })
        };

        fetch('https://httpbin.org/anything', options)
            .then(response => {
                if (response.ok) {
                    return response.json();
                }

                return Promise.reject(response.status);
            })
            .then(data => console.log(data))
            .catch(error => console.log(error));
    </script>
</head>
<body>
</body>
</html>