强制保留指定位小数

//强制保留指定位小数
function getFloatNum(num, index) {
    if(typeof num == "undefind" || num == null || num == "" || isNaN(num)) return num;
    if(!index)  index = 2;
    var _num = parseFloat(num).toFixed(parseInt(index));
    return _num;
};
console.log(getFloatNum(11,"3"),getFloatNum(11.1,"3"),getFloatNum("11.11","3"),getFloatNum("11.111",3),getFloatNum("11.1115",3)) // 11.000 11.100 11.110 11.111 11.111