什么是mb_convert_encoding（$ string，'utf-8'，'HTML-ENTITIES'）的替代品;？

I am looking to replace

 mb_convert_encoding($string, 'utf-8', 'HTML-ENTITIES');

with something else, because I do not have the mb module installed and cannot install it. Is there anything? I tried utf8_decode($string), but that didn't work.

This is different from the question listed, because it tries to do the reverse.

I want to take a string, for example, with ä in UTF8 and convert it into ä or its HTML entity as &#num;

If you don't have mb_convert_encoding you can try using a preg_replace_callback to UCS-4 encode the string and then use bin2hex, something like:

$string = "★ PHP UTF-8 Sucks! ★";
$entity = preg_replace_callback('/[\x{80}-\x{10FFFF}]/u', function ($m) {
    $char = current($m);
    $utf = iconv('UTF-8', 'UCS-4', $char);
    return sprintf("&#x%s;", ltrim(strtoupper(bin2hex($utf)), "0"));
}, $string);
echo $entity;

★ PHP UTF-8 Sucks! ★

You may consider the use of the MBString Polyfill library. This library adds MBString methods even if you do not have the extension installed on your platform.

I can fix my problem with this:

htmlspecialchars_decode( html_entity_decode( html_entity_decode( $string, ENT_QUOTES | ENT_XML1, 'UTF-8' ) ) );