逗号分隔，保留两位小数(计算工具中用到的)

代码：

//逗号分隔，保留两位小数(计算工具中用到的)
function fd_dStr(s, n)
{
    var nn=n;
    n = n > 0 && n <= 20 ? n : 2;
    s = parseFloat((s + "").replace(/[^\d\.-]/g, "")).toFixed(n) + "";
    var l = s.split(".")[0].split("").reverse(),
        r = s.split(".")[1];
    bjo = "";
    for(i = 0; i < l.length; i ++ )
    {
        bjo += l[i] + ((i + 1) % 3 == 0 && (i + 1) != l.length ? "," : "");
    }
 
    if(nn==0){
        return bjo.split("").reverse().join("");
    }else{
        return bjo.split("").reverse().join("") + "." + r;
    }
}

示例：

var $str="200241234.56789";
var $res=fd_dStr($str,2);
console.log($res);//200,241,234.57

var $str="200241234.56789";
var $res=fd_dStr($str,21);
console.log($res);//200,241,234.57

var $str="200241234.56";
var $res=fd_dStr($str,4);
console.log($res);//200,241,234.5600

var $str="200241234.566";
var $res=fd_dStr($str,0);
console.log($res);//200,241,234