Let's assume there's a text box somewhere on the page. Users can enter any number of any length, with spaces, hyphens, parentheses, etc. to define groupings. The system returns a list of what kinds of numbers that specific format could match. That is, an input of "111-11-1111" would return, among anything else applicable, "Social Security Number"; an input of "(111) 111-1111" would return "Canadian/American phone number"; an input of "1111 1111 1111 1111" would return "Credit card".
The implementation of this would be trivial, but is there a giant list out there of different number formats?