[Javascript] 숫자 3자리 단위마다 콤마(comma) 찍기

[Javascript] 숫자 3자리 단위마다 콤마(comma) 찍기 

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

How to print a number with commas as thousands separators in JavaScript

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

function comma(num){
    var len, point, str; 
       
    num = num + ""; 
    point = num.length % 3 ;
    len = num.length; 
   
    str = num.substring(0, point); 
    while (point < len) { 
        if (str != "") str += ","; 
        str += num.substring(point, point + 3); 
        point += 3; 
    } 
     
    return str;
 
}