var_dump(_bin2hex(htmlentities("\xf7\xbf\xbf\xff", ENT_QUOTES, "UTF-8")));
var_dump(_bin2hex(htmlentities("\xf8\x88\x80\x80\x80", ENT_QUOTES, "UTF-8")));
-echo "--\n";
-// UTF-8: with ENT_IGNORE
-var_dump(_bin2hex(htmlentities("\xc0\xa0\xc2\x80", ENT_QUOTES | ENT_IGNORE, "UTF-8")));
-var_dump(_bin2hex(htmlentities("\xe0\x80\x80\xe0\xa0\x80", ENT_QUOTES | ENT_IGNORE, "UTF-8")));
-var_dump(_bin2hex(htmlentities("\xf0\x80\x80\x80\xf0\x90\x80\x80", ENT_QUOTES | ENT_IGNORE, "UTF-8")));
-
echo "--\n";
// UTF-8: alternative (invalid) UTF-8 sequence
var_dump(_bin2hex(htmlspecialchars("\xc0\xa6", ENT_QUOTES, 'UTF-8')));
string(0) ""
string(0) ""
--
-string(4) "c280"
-string(6) "e0a080"
-string(8) "f0908080"
---
string(0) ""
string(0) ""
string(0) ""