Php Code : Log-In Page

Log-In Page in php

 
<html>

 <head>
  <title>Log-In Page</title>
 </head>

 <body>
 Please enter your user details to log-in here...

 <form action = "authenticate.php" method = "post">
 Username:<br>
 <input type = "text" name = "username">
 <br><br>
 Password:<br>
 <input type = "text" name = "password">
 <br><br>
 <input type = "submit" value = "Log In">
 </form>

 </body>

</html>

File: authenticate.php


<?php

$username = $_POST['username'];
$password = $_POST['password'];
$self =     $_SERVER['PHP_SELF'];
$referer =  $_SERVER['HTTP_REFERER'];

if( ( !$username ) or ( !$password ) )
{ header( "Location:$referer" ); exit(); }

$conn=@mysql_connect( "localhost", "userName", "password" ) or die( "Could not connect" );

$rs = @mysql_select_db( "my_database", $conn ) or die( "Could not select database" );
$sql = "select * from users where user_name=\"$username\" and password = password( \"$password\" )";
 
$rs = mysql_query( $sql, $conn ) or die( "Could not execute query" );

$num = mysql_numrows( $rs );

if( $num != 0 )
{ 
  $msg = "<h3>Welcome $username - your log-in succeeded!</h3>";
}
else
{
  header( "Location:$referer" ); exit(); 
}
?>

<html>

 <head>
  <title>Log-In Authenticated</title>
  </head>

  <body>
   <?php echo( $msg ); ?>
  </body>

</html>