숫자 3자리 단위마다 콤마(comma) 찍기

function numberWithCommas(x) {
    return x.toString().replace(/\B(?=(\d{3})+(?!\d))/g, ",");
}

참고 - 참고 : http://stackoverflow.com/questions/2901102/how-to-print-a-number-with-commas-as-thousands-separators-in-javascript

출처: https://fruitdev.tistory.com/160 [과일가게 개발자]