If you are posting the data on the same page you could do the following:
<?php
if(isset($_REQUEST["submit"])){
// mySQL code here
// return either success or failed
$confirmation="success";
}
?>
<html>
<head>
<title>Feedback</title>
</head>
<body>
<div>
<?php
if(isset($confirmation)){
echo $confirmation;
}
?>
</div>
<form method="post" action="">
<input type="text" name="username">
<input type="password" name="password">
<input type="submit" name="submit" Value="Submit">
</form>
</body>
</html>
If you are sending the data to a separate page:
On the receiving page:
<?php
// mySQL code here
// return either success or failed
//redirect to index.php with confirmation as true or false
header('location:index.php?confirmation=success');
?>
and on the page that you Sent the data from:
<html>
<head>
<title>Feedback</title>
</head>
<body>
<div>
<?php
//at index page where you want to display message
if(isset($_GET['confirmation']) && !empty($_GET['confirmation'])){
echo $_GET['confirmation'];
}
?>
</div>
<form method="post" action="uploaddata.php">
<input type="text" name="username">
<input type="password" name="password">
<input type="submit" name="submit" Value="Submit">
</form>
</body>
</html>
You can then use CSS3 animations to fade the message in and out for a better user experience :-)