PHP检查字符串编码和转化编码

<?php

$title = 'abc';
$encode = mb_detect_encoding($title, array('ASCII','UTF-8','GB2312','GBK','BIG5'));

echo $encode;
echo '<br>';
if ($encode != 'UTF-8'){
    $title = iconv($encode,'UTF-8',$title);
}

echo $title;
echo '<br>';
$encode = mb_detect_encoding($title, array('ASCII','UTF-8','GB2312','GBK','BIG5'));

echo $encode;
echo '<br>';