js保留两位小数，始终显示小数点后两位，没有的就补零

function toNum2(num) {
    if(!num){
        num=0
    }
    var formatNum = Math.round(num * 100) / 100;
    var strNum = formatNum.toString();
    var resNum = strNum.indexOf('.');
    if (resNum < 0) {
        resNum = strNum.length;
        strNum += '.';
    }
    while (strNum.length <= resNum + 2) {
        strNum += '0';
    }
    return strNum;
}

END.