add commas to integer

gistfile1.js

function addComma(num) {
	num = String(num);
	var len = num.length;
	var remainder = len % 3;
	var h = num.substring(0, remainder);
	var str = num.substring(remainder);
	var i = 0;
	var flag = str.length / 3;
	var result = h ? [h] : [];
	for (; i <f lag; i ++) {
		result.push(str.substring(i * 3, i * 3 + 3));
	}
	return result.join();
}

function addComma2 (num) {
	num = String(num);
	var reg = /(\d+)(\d{3})/;
	while (reg.test(num)) {
		num = num.replace(reg, '$1' + ',' + '$2');
	}
	return num;
}