หน้า index แบบนี้ เขามีโครงสร้างและวิธีเขียนยังไง ช่วยแนะนำทีครับ

<?php //index.php?>
<?php session_start();?>
<?php require 'makepage.php'; $MasterPage = 'master.php';?>
<?php if (0):?>
<?php endif;?>
<?php sb('title'); echo "หน้าแรก"; eb();//end title?>
<?php sb('head');?>
<?php eb();//endhead?>
<?php sb('content');
if(isset($_SESSION['user_class'])){
    echo"<script>window.location='main.php';</script>";
}
?>
<script type="text/javascript" src="https://www.google.com/jsapi"></script>
    <script type="text/javascript">
    showkey('username');
    //showkey('password2');
    function showkey(id){
     // Load the Google Onscreen Keyboard API
     google.load("elements", "1", {
         packages: "keyboard"
     });

     function onLoad() {
        var kbd = new google.elements.keyboard.Keyboard(
         [google.elements.keyboard.LayoutCode.ENGLISH],
         [id]);
     }

     google.setOnLoadCallback(onLoad);
    }
    </script>
<style>
.line{
border:none;    
}
</style>
<div align="center">
    <div class="login">
        <form action="login.php" method="post" autocomplete="off">
            <div align="left"><label for="username" align="left">ชื่อผู้ใช้</label></div>
            <input type="text" id="username" onclick="showkey('username')" name="username" class="form-control" placeholder="กรอกชื่อผู้ใช้">
            <div align="left"><label for="username" align="left">รหัสผ่าน</label></div>
            <input type="password" onclick="showkey('password2')" id="password2" name="password" class="form-control">
            <div align="center" style="margin-top:10px;">
                <button type="submit" class="btn btn-info">เข้าสู่ระบบ</button>
                <button type="reset" class="btn btn-default">ยกเลิก</button>
            </div>
        </form>
    </div>
</div>

<?php eb();// end content?>
<?php render();?>

<?php
/**
* @package        Joomla.Administrator
* @copyright    Copyright (C) 2005 - 2013 Open Source Matters, Inc. All rights reserved.
* @license        GNU General Public License version 2 or later; see LICENSE.txt
*/

// Set flag that this is a parent file
define('_JEXEC', 1);
define('DS', DIRECTORY_SEPARATOR);

if (file_exists(dirname(__FILE__) . '/defines.php')) {
    include_once dirname(__FILE__) . '/defines.php';
}

if (!defined('_JDEFINES')) {
    define('JPATH_BASE', dirname(__FILE__));
    require_once JPATH_BASE.'/includes/defines.php';
}

require_once JPATH_BASE.'/includes/framework.php';
require_once JPATH_BASE.'/includes/helper.php';
require_once JPATH_BASE.'/includes/toolbar.php';

// Mark afterLoad in the profiler.
JDEBUG ? $_PROFILER->mark('afterLoad') : null;

// Instantiate the application.
$app = JFactory::getApplication('administrator');

// Initialise the application.
$app->initialise(array(
    'language' => $app->getUserState('application.lang')
));

// Mark afterIntialise in the profiler.
JDEBUG ? $_PROFILER->mark('afterInitialise') : null;

// Route the application.
$app->route();

// Mark afterRoute in the profiler.
JDEBUG ? $_PROFILER->mark('afterRoute') : null;

// Dispatch the application.
$app->dispatch();

// Mark afterDispatch in the profiler.
JDEBUG ? $_PROFILER->mark('afterDispatch') : null;

// Render the application.
$app->render();

// Mark afterRender in the profiler.
JDEBUG ? $_PROFILER->mark('afterRender') : null;

// Return the response.
echo $app;