YA: Check User Cookie For Login WoC 20130620074829AAJvlEe

<?php
// Yahoo Ansers' Question: http://answers.yahoo.com/question/answer?qid=20130620074829AAJvlEe

// Variable to hold the message we want displayed.
$message = '';


// Check and see if the $_COOKIE['username'] exists
If(isset($_COOKIE['username'])) {

    require_once('connect.php');

    $username = mysql_real_escape_string( $_COOKIE['username'] );

    $sql = "SELECT user_id FROM users WHERE username='{$username}' LIMIT 1";

    $result = mysql_query($sql);

    // Check to make sure statement and query are good.
    if( !$result ){
        $message .= 'Internal Error: ' . mysql_error();
    }else if( mysql_num_rows($result) === 0){
        $message .= 'Welcome, Guest!<br />';
    }else{
        $row = mysql_fetch_assoc($result);
        $user_id = $row['user_id'];

        $message .= 'Welcome . ' . $username . '!<br /><br />';
        $message .= 'Your <a href="profile.php?id=' . $user_id . '">Profile Page</a> awaits.';
    }
} else {
    $message .= "Welcome, Guest! <br/>";
}

?>
<html>
    <head>
        <title>Home</title>
        <style type="text/css">
            a:link {
                color: blue;
                text-decoration: none;
            }
            a:visited {
                color: purple;
                text-decoration: none;}
            a:hover {
                color: black;
                text-decoration: none;
            }
            h3 {
                text-align: center;
            }
        </style>
    </head>
    <body>
        <h3>Home</h3>
        <hr />
        <br />
        <br />
        <?php echo $message; ?>
    </body>
</html>