jQuery - Number Counter with Commas

CountWithCommas.js

//Call the function on scroll
$(window).scroll(numberCounter);

//Check if in viewport function
function inViewport(el, val) {
    var docViewTop = $(window).scrollTop();
    var docViewBottom = docViewTop + $(window).height();

    var elTop = $(el).offset().top;
    var elBottom = elTop + $(el).height();

    return ((elTop + val <= docViewBottom));
}

//Counter Function
function numberCounter() {
    if (inViewport($('.stat-number'), 100)) {
        $('.stat-number').not('.counted').each(function () {
            var $this = $(this);

            $({Counter: 0}).animate({Counter: $this.text()}, {
                duration: 1000,
                easing: 'swing',
                step: function () {
                    $this.addClass('counted');
                    $this.text(commaSeparateNumber(Math.round(this.Counter)));
                }
            });
        });
    }
}


//Add Commas Function
function commaSeparateNumber(val) {
    while (/(\d+)(\d{3})/.test(val.toString())) {
        val = val.toString().replace(/(\d)(?=(\d\d\d)+(?!\d))/g, "$1,");
    }
    return val;
}