不舍入得到两个浮点数更可靠。

参考答案

VaR 数 = 10.5859; var fixed2FloatPoints = parseInt（number * 100） / 100; console.log（fixed2FloatPoints）;

谢谢你！

parseInt比Math.floor快

function floorFigure(figure, decimals){
    if (!decimals) decimals = 2;
    var d = Math.pow(10,decimals);
    return (parseInt(figure*d)/d).toFixed(decimals);
};

floorFigure(123.5999)    =>   "123.59"
floorFigure(123.5999, 3) =>   "123.599"

2021年6月更新

这将固定任何给定长度的数字而不舍入

let fixwithoutsurround = (v, l) => { const intPart = Math.trunc(v).toString() const fractionPart = v.toString().slice(v.toString(). indexof ('.') + 1) 如果(fractionPart。长度> l) { 返回(intPart.concat(数量”。’,fractionPart。片(0,l))) }其他{ const padding = intPart.concat('。’,fractionPart。padEnd (l ' 0 ')) 返回的 ｝ ｝ 12) console.log (FixWithoutRounding (123.123)

基于David D的回答:

function NumberFormat(num,n) {
  var num = (arguments[0] != null) ? arguments[0] : 0;
  var n = (arguments[1] != null) ? arguments[1] : 2;
  if(num > 0){
    num = String(num);
    if(num.indexOf('.') !== -1) {
      var numarr = num.split(".");
      if (numarr.length > 1) {
        if(n > 0){
          var temp = numarr[0] + ".";
          for(var i = 0; i < n; i++){
            if(i < numarr[1].length){
              temp += numarr[1].charAt(i);
            }
          }
          num = Number(temp);
        }
      }
    }
  }
  return Number(num);
}

console.log('NumberFormat(123.85,2)',NumberFormat(123.85,2));
console.log('NumberFormat(123.851,2)',NumberFormat(123.851,2));
console.log('NumberFormat(0.85,2)',NumberFormat(0.85,2));
console.log('NumberFormat(0.851,2)',NumberFormat(0.851,2));
console.log('NumberFormat(0.85156,2)',NumberFormat(0.85156,2));
console.log('NumberFormat(0.85156,4)',NumberFormat(0.85156,4));
console.log('NumberFormat(0.85156,8)',NumberFormat(0.85156,8));
console.log('NumberFormat(".85156",2)',NumberFormat(".85156",2));
console.log('NumberFormat("0.85156",2)',NumberFormat("0.85156",2));
console.log('NumberFormat("1005.85156",2)',NumberFormat("1005.85156",2));
console.log('NumberFormat("0",2)',NumberFormat("0",2));
console.log('NumberFormat("",2)',NumberFormat("",2));
console.log('NumberFormat(85156,8)',NumberFormat(85156,8));
console.log('NumberFormat("85156",2)',NumberFormat("85156",2));
console.log('NumberFormat("85156.",2)',NumberFormat("85156.",2));

// NumberFormat(123.85,2) 123.85
// NumberFormat(123.851,2) 123.85
// NumberFormat(0.85,2) 0.85
// NumberFormat(0.851,2) 0.85
// NumberFormat(0.85156,2) 0.85
// NumberFormat(0.85156,4) 0.8515
// NumberFormat(0.85156,8) 0.85156
// NumberFormat(".85156",2) 0.85
// NumberFormat("0.85156",2) 0.85
// NumberFormat("1005.85156",2) 1005.85
// NumberFormat("0",2) 0
// NumberFormat("",2) 0
// NumberFormat(85156,8) 85156
// NumberFormat("85156",2) 85156
// NumberFormat("85156.",2) 85156

滚动你自己的固定函数:为正值数学。地板很好。

function toFixed(num, fixed) {
    fixed = fixed || 0;
    fixed = Math.pow(10, fixed);
    return Math.floor(num * fixed) / fixed;
}

对于负数，数学。底部是值的整数。所以你可以用数学。装天花板。

的例子,

Math.ceil(-15.778665 * 10000) / 10000 = -15.7786
Math.floor(-15.778665 * 10000) / 10000 = -15.7787 // wrong.

截断不带零

function toTrunc(value,n){  
    return Math.floor(value*Math.pow(10,n))/(Math.pow(10,n));
}

or

function toTrunc(value,n){
    x=(value.toString()+".0").split(".");
    return parseFloat(x[0]+"."+x[1].substr(0,n));
}

测试:

toTrunc(17.4532,2)  //17.45
toTrunc(177.4532,1) //177.4
toTrunc(1.4532,1)   //1.4
toTrunc(.4,2)       //0.4

用零截断

function toTruncFixed(value,n){
    return toTrunc(value,n).toFixed(n);
}

测试:

toTrunc(17.4532,2)  //17.45
toTrunc(177.4532,1) //177.4
toTrunc(1.4532,1)   //1.4
toTrunc(.4,2)       //0.40