js中價格格式化

//轉換格式化###,###,##.00
     function number_format(num){
          num = parseFloat(num); 
        var SUM="";
        var sumFol = num.toFixed(2);
        var sumtotalStr = sumFol;
        var sumEndStr = sumtotalStr.slice(sumtotalStr.indexOf("."));
        var sumStr = sumtotalStr.slice(0,sumtotalStr.indexOf("."));
        if(num.toString().length <= 3) return num;
        if(sumStr.toString().length > 3){
            var count=0;
            if (sumStr.toString().length % 3 == 0) {
                count = sumStr.toString().length/3;
            }else{
                count = (sumStr.toString().length-sumStr.toString().length%3)/3;
            }
            var text = "";
            for(i=0;i<count;i++) {
                if((count-i-1)*3+sumStr.toString().length%3!=0) {
                    text=","+sumStr.slice((count-i-1)*3+sumStr.toString().length%3,(count-i-1)*3+sumStr.toString().length%3+3)+text;
                }else {
                    text=sumStr.slice((count-i-1)*3+sumStr.toString().length%3,(count-i-1)*3+sumStr.toString().length%3+3)+text;
                }
            }
            SUM = sumStr.slice(0,sumStr.toString().length % 3)+text+sumEndStr;
            return SUM; 
        }
        return sumFol ;
     }