strpos

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

説明

Returns the numeric position of the first occurrence of needle in the haystack string.

戻り値

Returns the position as an integer. If needle is not found, strpos() 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.