<form action="https://php.tomgdow.com" method="POST" id="form_one">
    <fieldset class="info">
        <label for="name">Name</label>
        <input type="text" id="name" name="param1">
        <span class="msg_name"></span><br>

        <label for="textarea" class="space_above">Comment</label><br>
        <textarea name="param2" id="textarea" cols="54" rows="10" maxlength="250"
            placeholder="Type heref"></textarea>

        <input type="submit" class="submit" value="Submit Me!">
    </fieldset>

    <fieldset class="output">
        <legend>Response</legend>
        <div id="message"></div>

        <div>
            <label for="out-name" class="hidden" id="label-out-name">
                Your name</label>
            <output for="name" id="out-name"></output>
        </div>
        <div>
            <label for="out-choice" class="hidden" id="label-out-choice">
                Your comment is </label>
            <output for="choice" id="out-choice"></output>
        </div>
    </fieldset>

    <fieldset>
        <legend>Server</legend>
        <label for="server-response" class="hidden" id="label-server-response">Full Server
            Response</label><br>
        <output id="server-response"></output>
    </fieldset>

</form>

async function sendData() {

    const formData = new FormData(form_one);

    try {
        const response = await fetch("https://php.tomgdow.com", {
            method: "POST",
            body: formData
        });

        let result = await response.text();
        let responseArray = result.split('&');

        document.getElementById('out-name').value = responseArray[0];
        document.getElementById('out-choice').value = responseArray[1];
        document.getElementById('server-response').value = result;

    } catch (e) {
        console.error(e);
    }
}

const idArray = ["label-out-name", "label-out-choice", "label-server-response",
    "out-name", "out-choice", "server-response"];

document.getElementById('form_one').addEventListener('submit', function (event) {

    event.preventDefault();
    const formData = new FormData(form_one);
    if (checkField(event, "name")) {

        sendData();

        let msg = "Greetings from the PHP Server (POST Method)";
        document.getElementById('message').innerText = msg;

        for (const key of formData.keys()) {
            console.log("%c %s", "color:red", key)
        }

        for (const elem of idArray) {
            document.getElementById(elem).style.visibility = "visible";
        }

    }

});

document.getElementById('name').addEventListener('focus', function () {
    document.getElementsByClassName('msg_name')[0].style.backgroundColor = "white";
    document.getElementsByClassName('msg_name')[0].innerText = "";

    for (const elem of idArray) {
        document.getElementById(elem).style.visibility = "hidden";
    }

    document.getElementById('name').value = "";
    document.getElementById('message').innerText = "";
    document.getElementsByTagName('textarea')[0].value = "";

});

// index.php (server)

<?php
  echo  
     htmlspecialchars($_POST["param1"])."&"
     .htmlspecialchars($_POST["param2"])."&"
     .htmlspecialchars($_SERVER['HTTP_HOST']);
?>