stripos

 int stripos ( string $haystack , string $needle [, int $offset = 0 ] ) 

説明

Returns the numeric position of the first occurrence of needle in the haystack string. Unlike strpos(), stripos() is case-insensitive.

戻り値

Returns the position as an integer. If needle is not found, stripos() will return boolean FALSE. Warning: This function may return Boolean FALSE, but may also return a non-Boolean value which evaluates to FALSE, such as 0 or "". Please read the section on Booleans for more information. Use the === operator for testing the return value of this function.