สอบถามโค้ด upload ไฟล์ด้วย Library Uploadify (jQuery)

<?php
/*
Uploadify v3.1.0
Copyright (c) 2012 Reactive Apps, Ronnie Garcia
Released under the MIT License <http://www.opensource.org/licenses/mit-license.php> 
*/
// Define a destination
$targetFolder = 'data/'; // Relative to the root

if (!empty($_FILES)) {
	$tempFile = $_FILES['Filedata']['tmp_name'];
	$targetFile = rtrim($targetFolder,'/') . '/' . $_FILES['Filedata']['name'];
	
	// Validate the file type
	$fileTypes = array('jpg','jpeg','gif','png','txt','zip','rar'); // File extensions
	$fileParts = pathinfo($_FILES['Filedata']['name']);
	
	
	if (in_array($fileParts['extension'],$fileTypes)) 
	//if (in_array(strtolower($fileParts['extension']),$fileTypes)) 
	{
		move_uploaded_file($tempFile,$targetFile);
		echo '1';	
	} 
	else 
	{
		echo 'Invalid file type.';
	}
}
?>