cms/installation/index.php

<?php
/**
 * @package    Joomla.Installation
 *
 * @copyright  Copyright (C) 2005 - 2015 Open Source Matters, Inc. All rights reserved.
 * @license    GNU General Public License version 2 or later; see LICENSE.txt
 */

if (version_compare(PHP_VERSION, '5.3.10', '<'))
{
	die('Your host needs to use PHP 5.3.10 or higher to run this version of Joomla!');
}

/**
 * Constant that is checked in included files to prevent direct access.
 * define() is used in the installation folder rather than "const" to not error for PHP 5.2 and lower
 */
define('_JEXEC', 1);

// Bootstrap the application
require_once dirname(__FILE__) . '/application/bootstrap.php';

// Get the application
$app = JApplicationWeb::getInstance('InstallationApplicationWeb');

// Execute the application
$app->execute();