Question

I’ve am using jQuery validation plugin to validate a mobile phone number and am 2/3 of the way there.

The number must:

• Not be blank – Done,
• Be exactly 11 digits – Done,
• Begin with ’07’ – HELP!!

The required rule pretty much took care of itself and and I managed to find the field length as a custom method that someone had shared on another site.

Here is the custom field length code. Could anyone please suggest what code to add where to also require it begin with ’07’?

$.validator.addMethod("phone", function(phone_number, element) {
var digits = "0123456789";
var phoneNumberDelimiters = "()- ext.";
var validWorldPhoneChars = phoneNumberDelimiters + "+";
var minDigitsInIPhoneNumber = 11;
s=stripCharsInBag(phone_number,validWorldPhoneChars);
return this.optional(element) || isInteger(s) && s.length >= minDigitsInIPhoneNumber;
}, "* Your phone number must be 11 digits");

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;
}
$(document).ready(function(){
$("#form").validate();
});

Answer 1

Thanks for all the answers. I’ve managed to come up with this using nnnnnn’s regular expression. It gives the custom error message when an incorrect value is entered and has reduced 35 lines of code to 6!

$.validator.addMethod("phone", function(phone_number, element) { 
  return this.optional(element) || /^07\d{9}$/.test(phone_number); 
}, "* Must be 11 digits and begin with 07");

$(document).ready(function(){
        $("#form").validate();
});

Extra thanks to nnnnnn for the regex! 😀