When filling in a form with real time validation and contextual help, how should one communicate the logic behind the telephone number validation?
For example, then contextual help would give hints such as:
- Your contact number should contain 10 or 11 digits
- The telephone number is either invalid or inappropriate
For the case of "The telephone number is either invalid or inappropriate" how would you tell - with a clear and transparent phrase - that the person needs to enter a valid number and what format to follow?