找了一下很快就找到了
function moneyFormat(str) {
if (str.length <= 3) {
return str;
}
else {
return moneyFormat(str.substr(0, str.length - 3)) + "," + (str.substr(str.length - 3));
}
}
2020-12-23補
//三位一撇
function three(num) {
const parts = num.toString().split('.');
parts[0] = parts[0].replace(/\B(?=(\d{3})+(?!\d))/g, ',');
return parts.join('.');// '$' +
}
參考網址avascript 數字字串三位一撇