JS保留4位小数(合集)

    //保留4位小数
    var number = 12.3321432;
    number = String(number).replace(/^(.*\..{4}).*$/,"$1");
    number = Number(number); // number = 12.3321
    //保留2位小数
    var reg = /^(.*\..{2}).*$/;
    var number2 = 12.3;
    number2 = String(number2).replace(reg ,"$1");
    number2 = Number(number2); // number2 = 12.3  不足保留位数不补0

getFloat = function(number, n) {
  n = n ? parseInt(n) : 0;
  if(n <= 0) {
    return Math.round(number);
  }
  number = Math.round(number * Math.pow(10, n)) / Math.pow(10, n); //四舍五入
  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

var a =123.456789;
alert(a.toFixed(4));// 四舍五入保留四位小数

  let numBoolean = Math.floor((this.editFormData.amount / this.thresholdYuan) * 10000) / 10000 >= 0.005