如何在JavaScript中成千上万？

Question

function multiplicar() {  m1 = document.getElementById("multiplicando").value;  m2 = document.getElementById("multiplicador").value;  m3 = m2 * 0.01;  x = m3 * parseFloat(m1);  x1 = x - 2380000;  document.getElementById("resultado").value = x1.toLocaleString();}const numberWithCommas = (x) => {  return x.toString().replace(/\B(?=(\d{3})+(?!\d))/g, ",");}function Sumar() {  var n1 = 1;  var n2 = document.getElementById('multiplicador').value;  var suma = parseInt(n1) + parseInt(n2);  document.getElementById("multiplicador").value = suma;  multiplicar();}function resta() {  var r1 = 1;  var r2 = document.getElementById('multiplicador').value;  var resta = parseInt(r2) - parseInt(r1);  document.getElementById("multiplicador").value = resta;  multiplicar();}<form id="multiplicar">  <div class="container-block">      <label>$</label> <input type="text" name="multiplicando" id="multiplicando" value="300000000" onChange="multiplicar();" onkeydown="noPuntoComa( event )" placeholder="Escribe el valor">  </div>  <div class="container-block">    <input type="button" onclick="resta();" value="-" class="resta">    <div class="container-input">      <input type="text" name="multiplicador" id="multiplicador" value="3" onChange="multiplicar();" onkeyUp="multiplicar();" min="0" pattern="^[0-9]+">      <label style="    right: 130px;">%</label>    </div>    <input type="button" onclick="Sumar();" value="+" class="suma">  </div>  <div class="container-block-resultado">      <label>$</label> <input type="text" id="resultado">  </div></form>我正在学习一些JavaScript，我想使用数千个数学运算。示例：300,000,000 * 3％= 900,000这是应该显示给用户的内容，用户可能会像计算器一样提高或降低百分比或值，而我找不到如何将数字相乘并以javascript中的百分比表示

Answer 1

因此，将您的字符串转换为数字。删除逗号并转换为数字。将百分比转换为十进制数。要添加时，请添加回逗号。

function removeComma (str) {

  return Number(str.replace(/,/g, ''))

}

function makePercentage (str) {

  return Number(str.replace(/%/, '')) / 100

}

function addCommas (number) {

  return number.toLocaleString()

}

var str1 = "300,000,000"

var str2 = "3%"

var mathResult = removeComma(str1) * makePercentage(str2)

var result = addCommas(mathResult)

console.log(result)