Further details for https://stackoverflow.com/questions/8218230

test.php

<?php

$char = 'イ';

// What's the UTF-8 encoding of this character? (This file is saved in UTF-8)
var_dump(bin2hex($char)); // e382a4

// What does another encoding look like?
// See http://www.fileformat.info/info/unicode/char/30a4/charset_support.htm
var_dump(bin2hex(mb_convert_encoding($char, "EUC-JP", "UTF-8"))); // a5a4

// Notice how ISO-8859-1 isn’t listed - イ can’t be represented in that encoding
var_dump(bin2hex(mb_convert_encoding($char, "ISO-8859-1", "UTF-8"))); // 3f ("?")

// Alternative output
// Also E_NOTICE: iconv(): Detected an illegal character in input string
var_dump(iconv("UTF-8", "ISO-8859-1", $char)); // false

// So what is the HTML-ENTITIES version?
var_dump(mb_convert_encoding($char, "HTML-ENTITIES", "UTF-8")); // &#12452;

// This is just the ASCII representation of the HTML entity:                & # 1 2 4 5 2 ;
var_dump(bin2hex(mb_convert_encoding($char, "HTML-ENTITIES", "UTF-8"))); // 262331323435323b