Hogyan oldjam meg, hogy a beléptetőm ki írja amikor nincs bele írva semmi azt hogy "kérem írd be a felhasználót. "?

[link]

User:admin

Pass:admin

Itt a login.php

<?php

$username = $_POST['username'];

$password = $_POST['password'];

if((isset($username)) && (isset($password)))

{

$connect = mysql_connect("","","") or die("Couldn't connect!");

mysql_select_db("xth_6732909_phplogin") or die ("Couldn't find db");

$query = mysql_query("SELECT * FROM users WHERE username='$username'");

$numrows = mysql_num_rows($query);

if ($numrows!=0)

{

while ($row = mysql_fetch_assoc($query))

{

$dbusername = $row['username'];

$dbpassword = $row['password'];

}

// check to see if they match!

if ($username==$dbusername&&$password==$dbpassword)

{

echo "You're in!";

}

else

echo "Incorrect password!";

}

else

die("That user doesn't exist!");

}

else

echo "Please enter username and password";

?>