login check

<?php
	session_start();

	$host = "localhost";
	$sqlusername = "SQL Username HIER";
	$sqlpassword = "SQL Wachtwoord HIER";
	$dbnaam = "Database naam HIER";
	$tabelnaam = "login";

	$con = mysqli_connect("$host", "$sqlusername", "$sqlpassword", "$db_name")or die("Kan niet connecten naar MySQL!");

	$username = $_POST['username'];
	$password = $_POST['password'];

	$sql = "SELECT * FROM $tbl_name WHERE username='$username' and password='$password";
	$result = mysqli_query($con, $sql);
	$count = mysqli_num_rows($result);

	if($count == 1){
		$_SESSION['username']=$username;
		$_SESSION['password']=$password;
		header('Location: login_success.php');
	}

	else {
		echo "Verkeerde naam, of wachtwoord";
	}
?>