/**

 * 判断文件是否合法

 * @param  $files

 * @param  $arrCode

 * @return number|boolean

 */

function checkFileType($files, $arrCode = array()){

	$file = @fopen($files['tmp_name'], "rb");

	$bin  = @fread($file, 2);

	fclose($file);

	$str  = @unpack('C2chars', $bin);

	$code = intval($str['chars1'].$str['chars2']);

	if(! is_array($arrCode))

		return $code;

	return array_key_exists($code, $arrCode);

}

//Demo

$arrCode = array(

	6063   => 'php',

	208207 => 'xls',

);

//如只允许上传php,和xls文件

$result = checkFileType($_FILES['file'], $arrCode);