jQuery Validating Australian Phone Numbers

Question

I am trying to get the value from an input box, validate & format the number, then update the input field.

I want it to validate all Australian phone numbers (mobile

Answer 1

I came up with 1 solution, not convinced how optimal it is, but someone may want to elaborate on it.

    function validatePhoneNumber(phone_number){
        var formatted = "";
        //remove all non-digits
        phone_number = phone_number.replace(/\D/g,'');
        //if number starts with 61, replace 61 with 0
        if (phone_number.match(/^61/)){
              phone_number = "0"+phone_number.slice(2);
        }

        if (phone_number.match(/^04/)){
            if (phone_number.length === 10){
                var formatted = phone_number.replace(/(\d{4})(\d{3})(\d{3})/g,"$1 $2 $3");
            } else {
                alert('Invalid phone number');
            }
        } else if (phone_number.match(/^02|03|07|08/)){
            if (phone_number.length === 10) {
                var formatted = phone_number.replace(/(\d{2})(\d{4})(\d{4})/g,"($1) $2 $3");
            } else {
                alert('Invalid phone number');
            }
        } else if (phone_number.length === 8){
            alert('Please use Area Code for landline numbers');
        } else {

            alert('Invalid phone number');
        }
        //update
        $("#phone").val(formatted);
    }

DEMO: https://jsfiddle.net/kb4u536a/