checklogin.php

<?php
// checklogin.php
// version 1.0
// Generation Time: 19/3/14
// Server version: 5.6.11 MySQL Community Server (GPL)
// PHP Version: 5.5.3
// Database: `user_logon`
// --------------------------------------------------
// This file allows a user to submit username and password.
// This file also establishes a connection to MySQL,
// checks whether the username/password combination is in the database.
// If exists, will redirect to login_success.php
// --------------------------------------------------

ob_start();
$host="localhost"; // Host name
$username="root"; // Mysql username
$password=""; // Mysql password
$db_name="UserData"; // Database name
$tbl_name="Users"; // Table name


// Connect to server and select database.
//conection:
$con = mysqli_connect("$host", "$username")or die("cannot connect");
mysqli_select_db($con, "$db_name")or die("cannot select DB");


// This defines $myusername and $mypassword
$myusername=$_POST['myusername'];
$mypassword=$_POST['mypassword'];


// Create the SQL query and run the query using mysqli_query()
$sql="SELECT * FROM Users WHERE username='$myusername' and password=SHA1('$mypassword')";
$result=mysqli_query($con, $sql);


// Mysql_num_row is counting table row
$count=mysqli_num_rows($result);
echo $count;

$counter =0;
$contents = file_get_contents('statistics.txt');
// If result matched $myusername and $mypassword, table row must be 1 row

if($count==1){($counter++ );
  // Redirect to file "login_success.php" if the username and password match
  header("Location:login_success.php");

  $total = $counter + $contents;

  $file = fopen("statistics.txt", "w")or die("unable to open file.");
 fwrite($file, "$total");
 fclose($file);

 }
 else {
   echo "Wrong Username or Password";

	$ErrorText = "Wrong username or password";
	$Date = " @" . date("d-m-y//h:i:sa");
	$myFile = "ErrorLog.txt"; //names the text file
	$fh = fopen($myFile, 'a') or die("can't open file");//Opens a connection to the file
	$stringData = $myusername.", ".$mypassword.", ".$ErrorText. $Date.PHP_EOL;
	fwrite($fh, $stringData);//Writes $stringData to the text file
	fclose($fh);

   //Write to txt files using $myusername and $mypassword
 }

ob_end_flush();
 ?>