<html>
    <head>
        <title>Post JSON to End2End Test</title>
    </head>
    <body>
        <button id="submit" onclick="sendJson()">Submit</button>
    </body>
    <script>
        function sendJson() {
            let xhr = new XMLHttpRequest();
            xhr.open("POST", "https://localhost:8085/post", true);
            xhr.setRequestHeader("Content-Type", "application/json");
            let data = JSON.stringify(
                { "hello": "world", "spam": "eggs" }
            );
            xh