if ($p) {
            $query = "UPDATE users SET password=PASSWORD('$p') WHERE user_id={$_SESSION['user_id']}";
            $result = mysql_query ($query);
            if (mysql_affected_rows() == 1)
            {

<?php

if (!isset($_SESSION['first_name'])) {
    header ("Location: http://" . $_SERVER['HTTP_HOST'] . dirname($_SERVER['PHP_SELF']) . "index.php");
    ob_end_clean();
    exit();
    
} else {
if (isset($_POST['submit'])) {
        
        if (isset($_POST['password']) == isset($_POST['password2'])){
            $p = isset($_POST['password1']);
        } else {
            $p = FALSE;
            echo '<p><font size="3">New password is not identical to your first entry!</font></p>';
        }
        } else {
            echo '<p><font size="3">Please enter password!</font></p>';    
        }
        
        if ($p) {
            $query = "UPDATE users SET password=PASSWORD('$p') WHERE user_id={$_SESSION['user_id']}";
            $result = mysql_query ($query);
            if (mysql_affected_rows() == 1)
            {
                echo '<font color="#33CC00"><h1>Congratulations,</h1><br><font color="#33CC00">Password changed successfully!<br><small>This page automatically refreshes every 5 seconds!';
        exit();
            } else {
                echo '<font color="red">Sorry for all inconvenience!</font><br />';
            }
        mysql_close();
        } else {
            echo '<font color="red">Try again!</font><br />';
        }
}
?>

<form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="POST">
    <p><small>New password:<font color="red">*</font> </small></b><input type="password" name="password1" size="20" maxlength="20"></p>
    <p><small>Confirm password:<font color="red">*</font> </small></b><input type="password" name="password2" size="20" maxlength="20"></p>
    <div align="center"><input type="submit" name="submit" value="Change"></div>
</form>

Please enter password!
Notice: Undefined variable: p in /var/www/change_password.php on line 33
Try again!

        if ($p) {