Add comma to textbox every three digits using jQuery

Question

I want to add comma to numbers every three digits on Textboxes.
I'm using this code but it not works. Where am I wrong?

  $(function () {
        $.fn.digits = function () {

            return this.each(function () {
                $(this).val($(this).val().replace(/(\d)(?=(\d\d\d)+(?!\d))/g, "$1,"));
            })
        }
        $("#Test").bind("change keyup keydown paste blur", function (e) {

            $("#Test").digits();
        });

    });

Answer 1

Try the following:

// "1234567".commafy() returns "1,234,567"
String.prototype.commafy = function() {
  return this.replace(/(.)(?=(.{3})+$)/g,"$1,")
}
$.fn.digits = function () {
    return this.each(function () {
        $(this).val($(this).val().commafy());
    })
}

JSFiddle http://jsfiddle.net/BrUVq/1/