Best way to check for multiple characters in a string
I have pages that print Code 39 bar codes; however, I do not have development in place to dissalow the entry of the invalid characters that Code 39 requires. For this discussion, you dont' really need to knwo what Code 39 is, just the list of invalid characters.
So, upon data entry, I would like to check the string to ensure the following special characters are NOT present in the string, if they are, then I'll alert them or do something:
Because there are so many characters to choose from, I am not certain the best code for this. What do you all suggest would be the best route to take?