(PHP 5 >= 5.2.0)
mb_stristr — Finds first occurrence of a string within another, case insensitive
mb_stristr() finds the first occurrence of needle in haystack and returns the portion of haystack. Unlike mb_strstr(), mb_stristr() is case-insensitive. If needle is not found, it returns FALSE.
The string from which to get the first occurrence of needle
The string to find in haystack
Determines which portion of haystack this function returns. If set to TRUE, it returns all of haystack from the beginning to the first occurrence of needle. If set to FALSE, it returns all of haystack from the first occurrence of needle to the end,
Character encoding name to use. If it is omitted, internal character encoding is used.
Returns the portion of haystack, or FALSE if needle is not found.