<?php

$host="localhost"; // Host name
$username=**********; // Mysql username
$password="*********"; // Mysql password
$db_name="**********"; // Database name
$tbl_name="users"; // Table name

// Connect to server and select databse.
mysql_connect ($host, $username, $password)or die("cannot connect to server");
mysql_select_db("$db_name")or die("cannot select DB");if(mysql_errno()) { echo ' Error '.mysql_errno().' '.mysql_error().'<br>'; }

// username and password sent from form
$myusername=$_POST['myusername'];
$mypassword=$_POST['mypassword'];
if($myusername<>'') {
// To protect MySQL injection (more detail about MySQL injection)
$myusername = stripslashes($myusername);
$mypassword = stripslashes($mypassword);
$myusername = mysql_real_escape_string($myusername);
$mypassword = mysql_real_escape_string($mypassword);
$sql="SELECT * FROM $tbl_name WHERE username='$myusername' and password='$mypassword'";


// Mysqli_num_row is counting table row
$count=mysql_num_rows($result);

// If result matched $myusername and $mypassword, table row must be 0 row
if($count==1){

// Register $myusername, $mypassword and redirect to file "login_success.php"
session_register("myusername");
session_register("mypassword");
header("location:login_success.php");
}
} else {
if($_POST['submit']<>'') #submit button like: <input type="submit" name="submit" value="Submit" >
{
#empty submit
echo 'Please fill all the fields';
} else {
#no submit yet.
echo 'Please submit the form.';
#link to the form.
}
}
echo "Wrong Username or Password";
?>