JS金額格式化

/格式化金額,小數點幾位
function fmoney(money,digit){
    if(null == money ){
        return "";
    }
    money = money +"";
    var array = money.split(".");
    var s =array[0];
    var r="";
    var m= s.substring(0,1);
    if('-'== m){
        s = s.substring(1);
    }else {
        m ="";
    }
    var f= s.split("").reverse();
    for(var i = 0;i< f.length;i++){
        r += f[i] + ((i + 1) % 3 == 0 && (i + 1) != f.length ? "," : "");
    }
    var after = "";
    if(array.length>1){
        after = array[1];
        if(after.length>digit){
            after =after.substring(0,digit);
        }
    }
    return m + r.split("").reverse().join("") + (array.length>1?"."+ after:"");
}

isString: function(str){
        return (typeof str=='string')&&str.constructor==String;
    },
    // 千分位顯示數據
    formatThousandths: function(num, decimal){
        if($.isString(num)) num = parseFloat(num);
        if(null == decimal || decimal == undefined) decimal = 2;
        return (num.toFixed(decimal) + '').replace(/\d{1,3}(?=(\d{3})+(.\d*)?$)/g, '$&,');
    }</pre>