if(isset($_POST)
{
	$username = mysqli_real_escape_string(stripslashes(htmlspecialchars($_POST["username"])));
	$password = mysqli_real_escape_string(stripslashes(htmlspecialchars(sha1($_POST["password"]))));
	$q = "SELECT * FROM user WHERE username = '$username' AND password = '$password' ";
	$r = mysqli_query($dbc, $q);
	if (mysqli_num_rows($r)==1)
	{
		$_SESSION['user_name'] = $_POST['username'];
		header('location:reg1.php');
	}
	else
	{
		echo 'error again!'.mysqli_error($dbc);
	}
}