js 千分位分割 正则替换

String.prototype.toThousands = function(){
　　return this.replace(/(\d)(?=(\d{3})+(?!\d))/g,"$1,")
}

'3800000.88'.toMoney()   //"3,800,000.88"

'38000.000'.toMoney()   //"38,000.000"