js中保留4位小数，超过4位截取保留4位，不足4位补足0

function getFloat(number,n)
{
    number = Number(number).toFixed(n); //补足位数

    return  number;
}


console.log(getFloat('0', 4)); //0.0000
console.log(getFloat('2.08', 4)); //2.0800
console.log(getFloat('2.08500', 4)); //2.0850
console.log(getFloat('2.08996', 4)); //2.0900
console.log(getFloat('2.08994', 4)); //2.0899