<?php
session_start();
//kiem tra dang nhap
if(isset($_POST['btnlogin'])){
	$txtUsername = $_POST['txtUr']; // lay username va pass cua nguoi dung
	$txtpassword = md5($_POST['txtPa']);

	if($txtUsername == ""||$txtpassword == ""){
		echo "Bạn không được phép bỏ trống";
	} else { //dung mysql kiem tra dang nhap nguoi dung
		$conn = mysqli_connect('localhost','root','','demo');

		$sql =
		'
		SECELET * FROM login
		WHERE username = "$txtUsername" AND password = "$txtpassword"
		';

		$result = mysqli_query($conn,$sql);

		if(mysqli_num_rows($result) == 0){   // dong nay bi loi ne :((((
		echo 'đã xảy ra lỗi';
		} else {
			//dang nhap dung
			$row = mysqli_fetch_array($result);
			$_SESSION['userid'] = $row['userid'];
			$_SESSION['username'] = $row['username'];
			$_SESSION['password'] = $row['password'];
			header('Location: index.php');
		}
	}
}

?>