To determine whether a string contains another string you can use the PHP function strpos().
int strpos ( string $haystack , mixed $needle [, int $offset = 0 ] )
CAUTION:
If the needle you are searching for is at the beginning of the haystack it will return position 0, if you do a == compare that will not work, you will need to do a ===
A == sign is a comparison and tests whether the variable / expression / constant to the left has the same value as the variable / expression / constant to the right.
A === sign is a comparison to see whether two variables / expresions / constants are equal AND have the same type - i.e. both are strings or both are integers.
