- utf8_encode: documentation ( source)
<?php
$str = '<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=iso-8859-7">
<title>test</title>
</head>
<body><p>aaaaa' . chr(0xAE) . chr(0xE3) . chr(0x80) . chr(0x90) .chr(0xE8) . 'zzzzz</p></body>
</html>';
$content = utf8_encode( $str );
$xml = new DOMDocument();
$xml->loadHTML($content);
echo @$xml->saveHTML();