A function to validate phone numbers using JavaScript and regular expressions. It will work with all valid US phone numbers in all popular formats.

1. function ValidatePhone(strPhone)
2. {
3.  var regPhone = /^(\+\d)*\s*(\(\d{3}\)\s*)*\d{3}(–{0,1}|\s{0,1})\d{2}(–{0,1}|\s{0,1})\d{2}$/;
4.  if (strPhone.match(regPhone))
5. {
6. return true;
7. }
8. else
9. {
10. return false;
11. }
12. }