I want to use this script to make a site where people can discuss unknown callers. Therefore, under "The question in one sentence:" i wanted people to be able to enter only 10 numbers. So in case the user entered anything else, or more, or less, than 10 numbers, then reject the question saying "Please enter only the number in the field under "number". So the field would accept xxx-xxx-xxxx or (xxx)-xxx-xxxx or just 1234567.
Any idea on how to do this i.e. what files to modify?