<?php
    if (!empty($_POST['username']))
    {
        require_once("connect.php");
    $username = mysql_real_escape_string($_POST['username']);
    $password = mysql_real_escape_string($_POST['password']);
    $query = mysql_query("SELECT * FROM members WHERE username='{$username}' AND password='{$password}'") or die(mysql_error());

        $row = mysql_fetch_array($query)
        or die ("Error - Could not login.");

        if (!empty($row['username']))
        {
            $_SESSION['username'] = $row['username'];
            echo "Welcome $_POST[username]! You've been successfully logged in.";
            exit();
        }
        else
        {
            echo "Error - Could not login.<br /><br />
                Try again.";
            exit();
        }
    }
    ?>
            <form action="login.php" method="post">
                <table width="100%" border="1" align="center" cellpadding="5" cellspacing="0">
                    <tr>
                        <td width="100%"><h3>Login</h3></td>
                    </tr>
                    <tr>
                        <td width="100%"><label>Username: <input type="text" name="username" size="25" value=""></label></td>
                    </tr>
                    <tr>
                        <td width="100%"><label>Password: <input type="password" name="password" size="25" value=""></label></td>
                    </tr>
                    <tr>
                        <td width="100%"><input type="submit" value="Login!"></td>
                    </tr>
                </table>
            </form>