// Downloaded from http://www.devscripts.net

<?PHP session_start(); ?>

<form action="index.php" method="post">
  <table width="100%" border="0" cellspacing="0" cellpadding="4">
    <tr> 
      <td><div class="small" align="right">User Name</div></td>
      <td><input name='username' type='TEXT' id="username" value="" maxlength='20'></td>
    </tr>
    <tr>
      <td><div class="small" align="right">Password</div></td>
      <td><input name="password" type="password" id="password" value=""></td>
    </tr>
    <tr> 
      <td><div align="center"></div></td>
      <td><div align="left"><input type="submit" name="userlogin" value="Login"></div></td>
    </tr>

  </table>
</form>

<?PHP
// check login and password
// connect and execute query
// db_connect is a script which provides a bd connection
include_once('db_connect.php');

if(isset($_POST['userlogin']))
{
    $username = strip_tags($_POST['username']) ;
    $password = md5($_POST['password']) ;
    $query = "SELECT UserID, UserName, Password from UserTable WHERE username ='$username' AND password = '$password'";
    $result = mysql_query($query) or die ("Error in query: $query. " . mysql_error());
    
    // if row exists - login/pass is correct
    if (mysql_num_rows($result) == 1)
   	{
        list($id, $username, $password) = mysql_fetch_row($result);
        // initiate a session
        // as we gonna log the user in too
        
        // register the user's ID
        session_register('UserID');
        session_register('Username');
          
        $_SESSION['UserID'] = $id;
        $_SESSION['Username'] = $username;
        // Redirect them as logon sucessful
    }
    else
    	// login/pass check failed
    	{
           // Handle the bad logon
    	}
}
?>