Online PHP editor | output for g4BOv

<?php // Now everything returns as expected. $str = "foo"; var_dump( mb_detect_encoding($str, 'UTF-8, UTF-8'), // string(5) "UTF-8" mb_detect_encoding($str, 'UTF-8, UTF-8', true) // string(5) "UTF-8" ); $str = "\xf8foo"; var_dump( mb_detect_encoding($str, 'UTF-8, UTF-8'), // bool(false) mb_detect_encoding($str, 'UTF-8, UTF-8', true) // bool(false) ); $str = "foo\xf8"; var_dump( mb_detect_encoding($str, 'UTF-8, UTF-8'), // bool(false) mb_detect_encoding($str, 'UTF-8, UTF-8', true) // bool(false) ); $str = "\xe1\xe9\xf3\xfa"; var_dump( mb_detect_encoding($str, 'UTF-8, UTF-8'), // bool(false) mb_detect_encoding($str, 'UTF-8, UTF-8', true) // bool(false) );