Ajax POST调用不发送或提交任何数据

Question

I am trying to make my submit button send data to my PHP file without reloading, however, when I use this call it doesn't send any data and neither is saved in my database.

$('#formSubmitData').on('submit', function(event) {
    event.preventDefault();
    var msg = $('#textareaSubmitData').val();
    $.ajax({
        url: 'searchData.php', //this is ALSO how the text is being send to the database to be retrieved later on.
        type: 'POST',
        data: {message:msg},
        success: function(data) {
            console.log(data);
            data = msg;
            alert(data);
        }
    });
});

The alert shows the correct value, but in my database, the rows remain empty.

How the PHP code looks like:.

    if (isset($_POST['submit']) && $_SERVER['REQUEST_METHOD'] === "POST") {
        include_once 'dbConn.php';

        $name = $_SESSION['userName'];
        $msg = $_POST['textareaSubmitData'];        

        $stmt = $conn->prepare("INSERT INTO messages (name, message) VALUES (?, ?)");
        $stmt->bind_param('ss', $name, $msg);

        $name = $_SESSION['userName'];
        $msg = $_POST['textareaSubmitData'];
        $stmt->execute();   

        $conn->close();
        $stmt->close();

    } else {
        header('Location: index.php?send=failure');
        exit();         
    }
}

Answer 1

Think there are 2 issues, the first is that you need to make sure the data to send is an object and not just a value...

data: { textareaSubmitData: msg },

The second is that when you try and process the data, your first line is...

if (isset($_POST['submit']) && $_SERVER['REQUEST_METHOD'] === "POST") {

So this is looking for some POST data in 'submit' - which you don't send. So as you (now) just send 'textareaSubmitData' - check if that is set...

if (isset($_POST['textareaSubmitData']) && $_SERVER['REQUEST_METHOD'] === "POST") {

Answer 2

You are sending the value of submit button in data. You need to send the form data to your server.

$('#formSubmitData').on('submit', function(event) {
    event.preventDefault();
    var data = new FormData(this);
    $.ajax({
        url: 'searchData.php', //this is ALSO how the text is being send to the database to be retrieved later on.
        type: 'POST',
        data: data,
        success: function(data) {
            data = msg;
            alert(data);
        }
    });
});

Answer 3

Also – definitively, "look at(!)" what is being sent, using the debugging features of your browser. When the AJAX call goes off, you can see an HTML POST being done – so, you can see exactly what the URL is, and exactly what data is (or, isn't) being supplied.

On the host side, you can also do things like print_r($_POST) so that you can once again see what PHP has received.

My experience is that, once you can see what's happening, debugging is very quick and easy. Whereas, guessing leads nowhere.