Validate phone number with JavaScript

Question

My regex of choice is:

/^[\+]?[(]?[0-9]{3}[)]?[-\s\.]?[0-9]{3}[-\s\.]?[0-9]{4,6}$/im

Valid formats:

(123) 456-7890
(123)456-7890
123-456-7890
123.456.7890
1234567890
+31636363634
075-63546725

First off, your format validator is obviously only appropriate for NANP (country code +1) numbers. Will your application be used by someone with a phone number from outside North America? If so, you don't want to prevent those people from entering a perfectly valid [international] number.

Secondly, your validation is incorrect. NANP numbers take the form NXX NXX XXXX where N is a digit 2-9 and X is a digit 0-9. Additionally, area codes and exchanges may not take the form N11 (end with two ones) to avoid confusion with special services except numbers in a non-geographic area code (800, 888, 877, 866, 855, 900) may have a N11 exchange.

So, your regex will pass the number (123) 123 4566 even though that is not a valid phone number. You can fix that by replacing \d{3} with [2-9]{1}\d{2}.

Finally, I get the feeling you're validating user input in a web browser. Remember that client-side validation is only a convenience you provide to the user; you still need to validate all input (again) on the server.

TL;DR don't use a regular expression to validate complex real-world data like phone numbers or URLs. Use a specialized library.

If you are looking for 10 and only 10 digits, ignore everything but the digits-

   return value.match(/\d/g).length===10;

/^[+]*[(]{0,1}[0-9]{1,3}[)]{0,1}[-\s\./0-9]*$/g

(123) 456-7890
+(123) 456-7890
+(123)-456-7890
+(123) - 456-7890
+(123) - 456-78-90
123-456-7890
123.456.7890
1234567890
+31636363634
075-63546725

This is a very loose option and I prefer to keep it this way, mostly I use it in registration forms where the users need to add their phone number. Usually users have trouble with forms that enforce strict formatting rules, I prefer user to fill in the number and the format it in the display or before saving it to the database. http://regexr.com/3c53v

What I would do is ignore the format and validate the numeric content:

var originalPhoneNumber = "415-555-1212";

function isValid(p) {
  var phoneRe = /^[2-9]\d{2}[2-9]\d{2}\d{4}$/;
  var digits = p.replace(/\D/g, "");
  return phoneRe.test(digits);
}

The following REGEX will validate any of these formats:

(123) 456-7890
123-456-7890
123.456.7890
1234567890

/^[(]{0,1}[0-9]{3}[)]{0,1}[-\s\.]{0,1}[0-9]{3}[-\s\.]{0,1}[0-9]{4}$/

Where str could be any of these formarts: 555-555-5555 (555)555-5555 (555) 555-5555 555 555 5555 5555555555 1 555 555 5555

function telephoneCheck(str) {
  var isphone = /^(1\s|1|)?((\(\d{3}\))|\d{3})(\-|\s)?(\d{3})(\-|\s)?(\d{4})$/.test(str);
  alert(isphone);
}
telephoneCheck("1 555 555 5555");