stristr ( string $haystack , mixed $needle [, bool $before_needle = FALSE ] ) : string
The string to search in
If needle is not a string, it is converted to an integer and applied as the ordinal value of a character. This behavior is deprecated as of PHP 7.3.0, and relying on it is highly discouraged. Depending on the intended behavior, the needle should either be explicitly cast to string, or an explicit call to chr() should be performed.
If TRUE, stristr() returns the part of the haystack before the first occurrence of the needle (excluding needle).
Returns the matched substring. If needle is not found, returns FALSE.
HAYSTACK NEEDLE | STRING
HAYSTACK NEEDLE | CHR