I'm very happy with how my first event registration turned out, but I have one nagging question.  We are having a 3-on-3 basketball tournament and need to gather emergency contact information for each participant.  I have added a registration attribute for the contact phone number, but I'd really like for it to format the number after it's entered, especially since it the participant's mobile phone will be formatted.  As I look through the list of Field Types, I don't see one for phone number. 

What is the best way to collect an emergency contact number and have it formatted?

Joe