I'm trying to post form data though a POST AJAX call in JavaScript for a chat system I'm creating, how come the following is not working? I tried to get some documentation but I cannot find it.
<div id="view-chat-form">
<input id="message" type="text" name="chat_message" placeholder="write a message..."/>,
<input type="button" value="send" onclick="sendData()"/>
</div>
and using the followin AJAX code to send the request without loading the page with an hashed string to hide the chat id
<script type="text/javascript">
function sendData(){
var cm = document.getElementById("message").value;
var xhttp = new XMLHttpRequest();
xhttp.open("POST", "chat_form.php", true);
xhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xhttp.send("q=<?php echo $hashed_id; ?>&chat_message=" + cm);
}
</script>
and the followin php code to insert the message into the messages table
<?php
include "session.php";
include "connection.php";
$id = "";
$hashed_id = mysqli_real_escape_string($connection, $_POST["q"]);
$sql = "SELECT * FROM chats WHERE SHA2(id, 512) = ?";
$stmt = mysqli_prepare($connection, $sql);
mysqli_stmt_bind_param($stmt, 's', $hashed_id);
mysqli_stmt_execute($stmt);
$result = mysqli_stmt_get_result($stmt);
$count = mysqli_num_rows($result);
if($count > 0){
$row = mysqli_fetch_assoc($result);
$id = $row["id"];
} else {
mysqli_free_result($result);
mysqli_close($connection);
header("Location: chat_error.php");
}
$msg = mysqli_real_escape_string($connection, $_POST["chat_message"]);
$username = $_SESSION["username"];
$date = date("d/m/Y");
$time = date("H:i:s");
$sql = "INSERT INTO chat_messages(chat_id, username, message, date, time) VALUES(?, ?, ?, ?, ?)";
$stmt = mysqli_prepare($connection, $sql);
mysqli_stmt_bind_param($stmt, 'dssss', $id, $username, $msg, $date, $time);
mysqli_stmt_execute($stmt);
?>
Don't understand why you are using php $_POST in javascript, it will not work. Try using document.getElementById() to grab the chat message.
The correct way is shown below.
<script type="text/javascript">
function sendData(){
var cm = document.getElementById("message").value;
var xhttp = new XMLHttpRequest();
xhttp.open("POST", "chat_form.php", true);
xhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xhttp.send("q=<?php echo $hashed_id; ?>&chat_message=" + cm);
}
</script>
Also in your PHP code, why using json_decode()? The post is not in JSON format. Correct that also.
Change below code
$data = json_decode(file_get_contents("php://input"));
$hashed_id = $data->q;
$msg = $data->chat_message;
to
$hashed_id = $_POST["q"];
$msg = $_POST["chat_message"];
Do something like this
<script type="text/javascript">
function sendData(){
var id = <?php echo $hashed_id; ?>;
var msg = <?php echo $_POST['chat_message']; ?>;
var xhttp = new XMLHttpRequest();
xhttp.open("POST", "chat_form.php", true);
xhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xhttp.send(id,msg);
}
</script>