alert from php page that data already received from arduino - php

Question

I'm currently doing a project regarding an attendance system using arduino uno and Ethernet shield. For now I have successfully saved the id I get from arduino to the database. My problem is how to make an alert or popup message that says the data has been received and stored in the database every time I receive data from arduino.
Thank you.
Below is my arduino code:
if (client.connect(myServer, 80)) {
Serial.println("Connecting to Database server");
// send the HTTP PUT request:
client.print("GET /school/inc/jaripelajar.php?P_ID=");
client.print(P_ID);
client.println(" HTTP/1.1");
client.println("Host: 192.168.137.1");
client.println("User-Agent: arduino-ethernet");
client.println("Connection: close");
client.println();
}
php code
// GET request
if (isset($_GET['P_ID'])){
$data1 = $_GET['P_ID'];
}
else{
//echo "Data not received";
}
// Initialize connection to MySQL database
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "school";
// Create connection
$conn = mysqli_connect($servername, $username, $password, $dbname);
// Check connection
if (!$conn) {
die("Connection failed: " . mysqli_connect_error());
}
//echo "Connected successfully <br>";
//Insert into database
$data1_sql = "INSERT INTO test (P_ID) VALUES ($data1);";
$data1_query = mysqli_query($conn, $data1_sql);