js-JavaScript实现数字的千位分隔符

function thousandSeparator(num) {
  return num && (num
    .toString().indexOf('.') != -1 ? num.toString().replace(/(\d)(?=(\d{3})+\.)/g, function($1, $2) {
      return $2 + ",";
    }) : num.toString().replace(/(\d)(?=(\d{3})+\b)/g, function($1, $2) {
      return $2 + ",";
    }));
}
console.log(thousandSeparator(1000000));//1,000,000
console.log(thousandSeparator(4656262.262));//4,656,262.262

根据freeyiyi1993的思路做了细微修改，原文有bug。