test.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script>
    "use strict";

    let requestOptions = {
        method: 'POST',
    };

    let username = 'testAccount'
    let password = 'test'

    fetch(`http://localhost:8080/login?username=${username}&password=${password}`, requestOptions)
        .then(response => response.json())
        .then(result => console.log(result))
        .catch(error => console.log('error', error));

</script>
</body>
</html>