PHP 我做了一个上传文件的小程序，求大神帮我看看！

if (!empty($_FILES)) {
$tempFile = $_FILES['Filedata']['tmp_name'];
$targetPath = $_SERVER['DOCUMENT_ROOT'] . $_REQUEST['folder'] . '/';
$targetFile = str_replace('//','/',$targetPath) . $_FILES['Filedata']['name'];
$targetFile = iconv("utf-8","gbk",$targetFile);

// $fileTypes = str_replace('*.','',$_REQUEST['fileext']);
// $fileTypes = str_replace(';','|',$fileTypes);
// $typesArray = split('\|',$fileTypes);
// $fileParts = pathinfo($_FILES['Filedata']['name']);

// if (in_array($fileParts['extension'],$typesArray)) {
// Uncomment the following line if you want to make the directory if it doesn't exist
// mkdir(str_replace('//','/',$targetPath), 0755, true);

move_uploaded_file($tempFile,$targetFile);
echo "1";
// } else {
// echo 'Invalid file type.';
// }
}