function format_number(n) {
var b = parseInt(n).toString();
var len = b.length;
if (len <= 3) { return b; }
var r = len % 3;
return r > 0 ? b.slice(0, r) + "," + b.slice(r, len).match(/\d{3}/g).join(",") : b.slice(r, len).match(/\d{3}/g).join(",");
}
原文：https://www.cnblogs.com/xuxian001/p/12120824.html