$.validator.addMethod("phone", function(phone_number, element) {
	var digits = "0123456789";
	var phoneNumberDelimiters = "()- ext.";
	var validWorldPhoneChars = phoneNumberDelimiters + "+";
	var minDigitsInIPhoneNumber = 10;
	s=stripCharsInBag(phone_number,validWorldPhoneChars);
	return this.optional(element) || isInteger(s) && s.length >= minDigitsInIPhoneNumber;
}, "Please enter a valid phone number");

function isInteger(s) {
	var i;
	for (i = 0; i < s.length; i++) {
		// Check that current character is number.
		var c = s.charAt(i);
		if (((c < "0") || (c > "9"))) return false;
	}
	// All characters are numbers.
	return true;
}
function stripCharsInBag(s, bag){
	var i;
	var returnString = "";
	// Search through string's characters one by one.
	// If character is not in bag, append to returnString.
	for (i = 0; i < s.length; i++) {
		// Check that current character isn't whitespace.
		var c = s.charAt(i);
		if (bag.indexOf(c) == -1) returnString += c;
	}
	return returnString;
}